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ORGANIC  CHEMISTRY. 


LEFFMANN   AND   LAWALL. 


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SANITARY  RELATIONS  OF  THE  COAL-TAR  COLORS. 

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TEXT-BOOK 


ORGANIC  CHEMISTRY 


HENRY  LEFFMANN,  A.M.,  M.D. 

Professor  of  Chemistry  at  the  Wagner  Free  Institute  of  Science  of  Philadelphia  and  at 
The  Woman's  Medical  College  of  Pennsylvania 


CHARLES  H.  LAWALL,  PH.G. 

Instructor  in  Pharmacy  and  Pharmaceutical  Arithmetic  at  the  Philadelphia  College  of 
Pharmacy  ;  Chemist  to  the  Dairy  and  Food  Commissioner  of  Pennsylvania 


California  CoIEogo  of-Pharmacy 


WITH  ILLUSTRATIONS  AND  EXPERIMENTS 


PHILADELPHIA 

P.  BLAKISTON'S  SON  &  CO. 

1012    WALNUT    STREET 
1905 


COPYRIGHT,   1904,  BY  P.  BLAKISTON'S  SON  &  Co. 


PP.ESS  or  WM.  r.  FELL  COMPANY 


PREFACE. 


This  book  is  offered  as  an  aid  to  the  study  of  organic 
chemistry  in  connection  with  general  and  professional  col- 
lege courses.-  The  difficulty  in  the  preparation  of  such  a 
work  is  to  determine  what  to  exclude.  We  have  endeav- 
ored to  give  consideration  to  the  more  important  features 
of  the  science,  especially  in  its  applications.  Polarisa- 
tion of  light  has  been  treated  in  some  detail  on  account  of 
the  importance  of  it  in  the  study  of  molecular  structure. 

Some  descriptive  topics  that  are  often  passed  over  very 
briefly  have  been  given  considerable  space.  Among  these 
are  to  be  noted  the  sections  on  Enzyms,  Purins,  Alkaloids 
and  Proteids. 

The  experiments  have  been  selected  with  a  view  of 
illustrating  all  the  important  types  of  organic  compounds 
and  reactions,  and  at  the  same  time  avoiding  danger  to 
the  student  and  tediousness  and  complexity  of  manipu- 
lation. 

All  temperatures  are  centigrade. 

119  SOUTH  FOURTH  ST.,  PHILADELPHIA, 

October,   1904.  C.    H.    L. 


42; 


CONTENTS. 


PAGES 

PRINCIPLES  .  . . 9-48 

Proximate  and  Ultimate  Composition — Physico- 
chemical  Data — Derivatives  and  Synthetic  Com- 
pounds— Transformations — Structure  and  Classi- 
fication— Percentage  Composition  and  Formulas 
— Optical  Activity — Isomerism — Organic  Radi- 
cles— Homologous  Series — General  Formulas — 
Nomenclature . 
DESCRIPTIVE  CHEMISTRY 49-215 

ALIPHATIC  COMPOUNDS. 

Hydrocarbons — Paraffins  and  Derivatives — Alco- 
hols —  Ethers,  Esters  —  Aldehydes  —  Ketones 
— Fatty-acids — Olefins  and  Derivatives — Meth- 
enyl  and  Derivative — Fats — Allyl  and  Deriva- 
tives— Carbohydrates — Glucosides . 

CYCLIC  COMPOUNDS. 

Homocyclic  Compounds:  Benzene  and  Deriva- 
tives— Naphthalene  and  Derivatives  Anthra- 
cene— Coal-tar  Colors. 

Ter penes:    Camphors — Essential  Oils — Resins. 
Heterocyclic  Compounds:  Pyridin  and  Derivatives 
— Quinolin . 

CYANOGEN  AND  DERIVATIVES:  Cyanides — Cyanates — 
Thiocyanates — Fulminates — Hydrazoates. 

AMMONIUM     DERIVATIVES:      Amines — Amides — Urea 
— Amido  Acids. 

Azo-    HYDRAZO-   AND   DIAZO-COMPOUNDS:     Diazoben- 
zene — Phenylhydrazin — Diazo-  reaction . 

ALKALOIDS. 

Ptomaines — Leucomaines — Purins . 

PROTEIDS  OR  ALBUMINOIDS:  Lecithins. 

ENZYMS. 

INDEX. 


ORGANIC  CHEMISTRY. 


PRINCIPLES. 

ORGANIC  CHEMISTRY  is  primarily  the  chemistry  of  sub- 
stances produced  by  living  tissues.  These  are  very  numer- 
ous, and  other  bodies  can  be  obtained  from  them,  which 
are  analogous  to  the  primary  organic  bodies,  and  are  in- 
cluded in  the  same  groups.  Transformations  and  modi- 
fications may  be  carried  so  far  as  to  produce  substances 
which  are  clearly  inorganic,  consequently  it  is  not  pos- 
sible to  establish  a  distinct  boundary  between  inorganic 
and  organic  chemistry.  It  was  formerly  supposed  that 
organic  bodies  are  distinct  in  that  the  original  compounds 
could  only  be  produced  by  vital  action,  but,  in  1828, 
Wohler  succeeded  in  producing  urea  by  heating  ammonium 
cyanate,  and  thus  set  aside  the  supposed  distinction. 
Since  that  time  many  similar  results  have  been  obtained, 
and  it  is  now  generally  believed  that  the  chemical  affinities 
concerned  in  the  formation  of  compounds  by  living  tissues 
are  the  same  as  those  operating  in  inorganic  bodies.  It 
must,  however,  not  be  supposed  that  the  chemistry  of  vital 
action  has  been  solved,  or  even  brought  into  entire  analogy 
with  inorganic  chemistry.  Many  points  yet  remain  to 
be  explained. 

A  characteristic  of  the  products  of  vital  action  is  that 
they  all  contain  carbon,  hence  it  has  been  proposed  to  sub- 

9 


10  ORGANIC    CHEMISTRY. 

stitute  for  organic  chemistry  the  title  "Chemistry  of  the 
Carbon  Compounds."  No  special  advantage  is  gained 
by  this.  Moreover,  several  compounds  containing  silicon 
in  combinations  analogous  to  natural  organic  bodies  have 
been  obtained,  so  that  the  later  title  is  equally  insufficient. 

Carbon,  hydrogen,  oxygen  and  nitrogen  are  most 
abundant  in  organic  compounds;  sulphur  and  phosphorus 
are  present  in  the  complex  forms  that  are  found  in  tissues 
of  higher  function.  Iron  is  found  in  several,  among  which 
are  the  coloring  matters  of  blood  and  green  vegetable 
tissue.  Copper  is  also  noted  in  a  few  cases.  By  lab- 
oratory methods  many  substances  have  been  obtained 
into  which  other  elements,  e.  g.,  chlorine,  bromine,  iodine, 
mercury  and  arsenic,  have  been  introduced.  These  are 
often  analogous  in  many  ways  to  natural  organic  bodies, 
but  not  equivalent  to  them  in  biologic  function. 

The  following  list  of  bodies  from  natural  sources  will 
illustrate  the  degrees  of  complexity  exhibited  by  organic 
compounds  : 

C10H16  .............  Terpene. 

CaH22On  ...........  Cane  sugar. 

C10H14N2  ...........  Nicotine  (from  tobacco). 

C17H19NO3  ..........  Morphine  (from  opium). 

C2H7NSO3  ..........  Taurin  (from  bile). 

C3H9PO6  ...........  Glycerophosphoric  acid  (from  brain  tissue)  . 

B  .......  Hematin  (from  blood  corpuscles). 


Proximate  and  Ultimate  Composition.  —  The  tissues  of 
plants  and  animals,  or  the  immediate  products  of  their 
transformations,  are  generally  mixtures  of  several  inde- 
pendent substances.  Butter  is  a  mixture  of  four  or  five 
fats  common  rosin  contains  two  or  sometimes  three 
distinct  bodies;  opium  and  Peruvian  bark  are  still  more 
complicated,  and  brain  and  muscle  structures  are  so  com- 


PRINCIPLES.  II 

plex  that  as  yet  complete  analyses  have  not  been  made 
of  them.  The  substances  which  thus  exist  naturally  in  a 
state  of  mixture  are  called  proximate  principles;  the 
separation  and  identification  of  them  is  called  proximate 
analysis,  and  such  of  them  as  give  characteristic  qualities  to 
the  articles  in  which  they  occur  are  often  called  active 
or  essential  principles;  atropine,  for  instance,  is  the  active 
principle  of  belladonna,  for  although  many  different  bodies 
are  contained  in  belladonna,  atropine  is  the  one  upon  which 
its  physiological  activity  mainly  depends.  The  ultimate 
constituents  of  any  substance  are  the  elements,  e.  g.,  carbon 
and  hydrogen,  that  it  contains;  the  detection  of  these 
elements  and  determination  of  their  amount  is  ultimate 
analysis.  This  is  simple  in  principle  but  in  practical 
operation  involves  much  care  and  skill.  The  following 
is  an  outline  of  the  more  important  procedures: 

Carbon  and  hydrogen  are  determined  by  burning  a 
weighed  portion  of  the  substance  in  a  current  of  oxygen 
or  in  contact  with  some  oxidising  agent.  The  carbon  is 
converted  into  carbon  dioxide,  the  hydrogen  into  water. 
These  are  absorbed  by  suitable  materials  in  separate 
vessels  and  the  increase  in  weight  of  these  will  permit  of 
calculation  of  the  carbon  and  hydrogen  in  the  substance. 
If  oxygen  is  the  only  other  element  present  it  is  deter- 
mined by  difference.  Nitrogen  is  determined  either  by 
measuring  it  free,  or  by  conversion  into  amine  (ammonia), 
NH3.  A  method  now  much  used  is  to  heat  the  sub- 
stance with  strong  sulphuric  acid  with  or  without  special 
oxidising  agents,  by  which  the  nitrogen  is  converted  into 
ammonium  sulphate.  This  is  termed  the  Kjeldahl  method. 
Chlorine,  iodine,  and  other  unusual  elements  require  special 
methods  that  need  not  be  described  here.  Sulphur  is  usu- 
ally converted  into  sulphate  by  oxidation. 


12  ORGANIC    CHEMISTRY. 

Nitrogen  may  be  detected  in  many  substances  by  con- 
version into  cyanide.  For  experimental  illustration  of 
this,  see  under  "Cyanogen." 

Physico-chemical  data  (constants)  are  of  value  in  iden- 
tifying organic  bodies,  ascertaining  purity  and  elucidating 
formulas.  The  following  are  the  more  widely  applicable 
methods : 

Specific  Gravity. — Specific  gravities  of  liquids  and  solids 
are  generally  expressed  by  comparison  with  water.  Con- 
fusion and  inconvenience  have  arisen  from  the  fact  that 
results  have  been  referred  to  water  at  different  temperatures 
as  unity.  The  temperatures  of  observation  and  com- 
parison should  always  be  expressed.  ~~  indicates  a 
determination  at^  100°  and  comparison  with  water  at  15.5° 
as  unity.  It  is  best  to  compare  the  substance  and  the 
standard  at  the  same  temperature. 

Pyknometer  or  Specific -gravity  Bottle. — This  is  a  generally 
applicable  means  of  determining  specific  gravity,  and  is 
capable  of  furnishing  good  results.  It  is  a  bottle — with  a 
perforated  stopper — adjusted  to  hold  a  certain  weight  of 
water  at  a  standard  temperature,  usually  15.5°.  Bottles  as 
sold  are  often  inaccurate.  The  weight  of  water  that  a 
bottle  holds  should  be  carefully  determined. 

Sprengel  Tube. — This  is  a  form  of  pyknometer  with 
which  a  high  degree  of  accuracy  is  attainable;  it  is  es- 
pecially suitable  for  determinations  at  the  boiling-point  of 
water.  It  consists  essentially  of  a  thin  glass  U-tube  ter- 
minating in  two  capillary  ends  bent  at  right  angles  and  each 
provided  with  a  ground  cap.  One  of  these  capillary  tubes 
must  have  a  smaller  caliber  than  the  other — not  larger  than 
0.25  mm.  The  larger  tube  should  bear  a  mark  at  m.  The 
tube  is  filled  by  immersing  b  in  the  liquid  under  examina- 
tion, connecting  the  smaller  end  with  a  large  glass  bulb, 


PRINCIPLES.  13 

and  applying  suction  to  the  latter  by  means  of  a  rubber 
tube.  If  now  the  rubber  tube  be  closed,  the  glass  tube 
will  fill  automatically.  It  is  placed  in  water,  the  ends 
being  allowed  to  project,  and  the  water  is  brought  to 
the  proper  temperature.  A  conical  flask  may  be  used 
to  contain  the  water,  the  ends  of  the  Sprengel  tube 
being  supported  by  the  neck.  The  mouth  of  the  flask 


FIG.   i. 


FIG.  2. 


should  be  loosely  covered.  As  the  liquid  expands  it 
will  drop  from  the  larger  orifice.  When  this  ceases,  the 
liquid  is  adjusted  to  the  mark  at  m.  If  beyond  the  point, 
a  little  may  be  extracted  by  means  of  a  roll  of  paper.  The 
tube  is  then  taken  out  of  the  bath,  the  caps  adjusted, 
the  whole  thoroughly  dried,  allowed  to  cool,  and  weighed. 
The  same  operation  having  been  performed  with  dis- 


I4  ORGANIC    CHEMISTRY. 

tilled  water,  the  calculation  of  the  specific  gravity  is  made 
as  usual. 

Westphal  Balance. — This  affords  a  convenient  means  of 
determining  specific  gravity.  It  consists  of  a  delicate  steel- 
yard provided  with  a  counterpoised  plummet.  The  latter, 
being  immersed  in  the  liquid,  the  equilibrium  is  restored  by 
means  of  weights  or  riders,  the  value  of  which  is  directly 
expressed  in  figures  for  the  specific  gravity  without  calcula- 


FIG.  3. 

tion.  Thus,  the  rider  A1  is  of  such  a  weight  as  to  express 
the  first  decimal  place,  and  will  be  represented  by  any  of 
the  figures  from  o  to  9  according  to  its  position  on  the  beam. 
Similarly  the  riders  A ,  B  and  C  furnish  the  figures  for  the 
second,  third  and  fourth  decimal  places  respectively.  The 
weight  A2  is  used  in  the  case  of  liquids  heavier  than  water. 
The  ordinary  form  of  Westphal  balance  is  untrust- 
worthy, but  good  instruments  are  made  by  some  European 
manufacturers. 


PRINCIPLES.  15 

The  principle  of  the  hydrostatic  balance  may  be  applied 
by  using  a  plummet  (that  sold  with  the  Westphal  balance 
will  serve)  with  the  ordinary  analytic  balance.  Testtubes 
weighted  with  mercury  and  sealed  in  the  flame  may  also  be 
used.  The  plummet  is  suspended  to  the  hook  of  the  bal- 
ance by  means  of  a  fine  platinum  wire.  The  specific 
gravity  of  any  liquid  may  be  determined  by  noting  the  loss 
of  weight  of  the  plummet  when  immersed  in  the  liquid  and 
dividing  this  by  the  loss  in  pure  water. 

Hydrometers  are  much  used  for  the  determination  of  the 
specific  gravity  of  liquids,  but  the  indications  are  less 
reliable  than  by  the  foregoing  methods .  Sensitive  hydrom- 
eters with  slender  stems,  and  accurately  graduated,  are 
now  obtainable.  These  are  capable  of  furnishing  good 
results.  Care  should  be  taken  to  make  the  reading  at  the 
top,  center  or  bottom  of  the  meniscus  according  to  the 
method  used  in  the  graduation  of  the  instrument.  In- 
struments intended  for  use  with  opaque  liquids  should  be 
graduated  to  be  read  at  the  top  of  the  meniscus. 

The  actual  specific  gravity  of  any  substance  is  the  ratio 
of  its  density  at  a  given  temperature  to  that  of  water  at  the 
same  temperature.  Statements  made  upon  any  other  basis 
than  this  may  be  converted  into  actual  specific  gravity 
by  calculation  from  the  table  of  density  of  water.  Thus, 
a  determination  of  specific  gravity  of  0.8000  at  ^  may 
be  converted  into  actual  specific  gravity  (—5)  as  follows : 

Density  of  water  at     15°  =  0.99916 
100°   =  0.95866 
i 00°  i 00° 

15°"  Too5 

Therefore,  95866  :  0.99916  :  :  0.8000  :  0.8337  (actual  specific  gravity 
at  100°). 

Melting  and  Solidifying  Points. — The  determination  of 


ORGANIC    CHEMISTRY. 


these  is  often  difficult.  Many  substances,  especially  fats, 
assume  conditions  exhibiting  abnormal  melting-points, 
and  also  frequently  solidify  at  a  temperature  very  different 
from  that  at  which  they  melt.  If,  in  the  preparation  of 
any  substance  for  determining  its  melting-point,  it  is 
necessary  to  make  a  previous  fusion,  the  mass  should  be 
allowed  to  rest  not  less  than  twenty-four  hours  after 

solidification  before  making 
the  experiment.  Chemists 
disagree  as  to  whether  the 
melting-point  should  be  con- 
sidered to  be  that  at  which 
the  substance  begins  to  be 
liquid  or  that  at  which  the 
liquid  is  perfectly  clear  Ordi- 
nary thermometers  are  fre- 
quently inaccurate,  the  error 
amounting  to  a  degree  or  more. 
No  observations  in  which  pre- 
cision is  required  should  be 
made  with  unverified  instru- 
ments. 

The  following  method  for 
determining  melting-points  is 
suitable  for  many  technical 

purposes.  By  substituting  strong  brine  or  glycerol  for 
the  water  in  the  bath  observations  may  be  made  at  tem- 
peratures beyond  the  limits  of  o°  and  100°. 

The  substance  is  heated  to  a  temperature  slightly  above 
its  fusing-point,  drawn  into  a  very  narrow  glass  tube,  and 
allowed  to  solidify  for  not  less  than  twenty-four  hours.  The 
tube,  open  at  both  ends,  is  attached  by  a  wire  or  rubber  ring 
to  a  thermometer  so  that  the  part  containing  the  substance 


FIG.  4. 


PRINCIPLES. 


is  close  to  the  bulb.  The  apparatus,  immersed  in  water,  is 
heated  at  a  rate  not  exceeding  0.5°  per  minute  until  fusion 
takes  place,  when  the  temperature  is  noted.  The  tempera- 
ture is  allowed  to  fall  and  the  point  at  which  the  sub- 
stance becomes  solid  is  also  observed.  To  insure  uniform 
and  gradual  heating,  it  is  necessary  to  immerse  the  vessel 
containing  the  thermometer  and  tube  in 
another  vessel  filled  with  water  (Fig.  4). 

Boiling-point. — For  the  determination  of 
boiling-point  the  apparatus  shown  in  Fig.  5 
is  convenient.  The  thermometer  is  inclosed 
in  an  outer  tube,  so  that  the  portion  of  the 
scale  to  which  the  mercury  rises  is  im- 
mersed in  the  vapor.  If  this  is  not  done, 
a  correction  must  be  applied  for  the  error 
produced  by  the  cooling  of  the  thermom- 
eter tube.  The  bulb  of  the  thermometer 
does  not  reach  into  the  liquid.  A  few  frag- 
ments of  pumice-stone  or  broken  clay 
pipestems  will  prevent  bumping.  The 
exit -tube  at  the  lower  end  of  the  wide 
tube  connects  with  a  condenser.  The 
barometric  pressure  must  always  be  noted 
and  allowance  made  for  the  variation  from 
the  standard  pressure,  760  mm. 

Vapor  Density. — This  is  the  density  of 
the  substance  in  a  state  of  gas  as  compared  with  some 
standard  (generally  hydrogen)  at  the  same  temperature 
and  pressure.  The  determination  is  largely  used  in  organic 
chemistry,  and  several  methods  of  procedure  have  been 
devised.  The  following,  due  to  Victor  Meyer,  is  the 
simplest : 

Fig.  6  shows  the  apparatus.     A  narrow  glass  tube  BA 


FIG.  5. 


ORGANIC    CHEMISTRY. 


is  expanded  at  the  closed  end  and  arranged  at  the  open  end 
to  receive  a  caoutchouc  stopper.  C  is  a  short  delivery  tube 
which  passes  under  the  collecting  tube  in  the  pneumatic 
trough.  The  outer  cylinder  F,  containing  the  tube  BA ,  is 

filled  with  some  liquid  of 
known  boiling  point  higher 
than  that  of  the  substance 
to  be  tested.  A  portion  of 
the  substance  to  be  tested  is 
weighed  into  a  small  tube 
and  dropped  into  the  inner 
tube.  It  vaporises  and  drives 
out  an  equal  volume  of  air 
which  is  collected  in  the  tube 
E.  By  this  means  the  vol- 
ume of  vapor  produced  by 
a  given  weight  of  the  body 
is  determined,  and  by  calcu- 
lation with  necessary  correc- 
tions the  vapor  density  is 
obtained. 

Freezing  Point  of  Solution, 
Cryoscopy. — This  method , 
originally  applied  for  de- 
termination of  molecular 
weights,  is  also  used  as  a 
clinical  test,  observations 
being  made  especially  with 
urine  and  blood.  The  de- 
pression of  the  freezing  point  of  these  is  regarded  as  of  con- 
siderable value  in  diagnosis.  In  this  clinical  application 
calculations  of  molecular  weight  are  not  made ,  the  data  being 
interpreted  by  comparison  with  the  average  of  normal  fluids. 


FIG.  6. 


PRINCIPLES. 


An  apparatus  shown  in  Fig.  7  is  used.  The  inner  tube 
.4,  provided  with  a  thermometer, 
stirrer  and  a  side  tube,  contains 
the  solution  to  be  tested.  It  is 
fastened  by  a  cork  in  the  wider 
tube  B  and  the  whole  is  supported 
in  the  vessel  C  (about  2500  c.c. 
capacity)  by  means  of  a  metallic 
cover.  In  C  is  the  freezing  mix- 
ture which  can  be  stirred  by 
means  of  the  rod  shown.  By 
this  arrangement  the  solution  is 
separated  from  the  cooling  mix- 
ture by  air  and  the  cooling  is 
uniform  and  gradual.  For  accu- 
rate determination  the  thermom- 
eter should  read  at  least  to  0.02°. 
It  is  not  necessary  to  observe 
actual  temperatures,  but  merely 
the  degree  of  depression  as  com- 
pared with  the  freezing  point  of 
the  pure  solvent. 

Polarimetry. — Polarimeters  are 
instruments  used  to  measure  the 
extent  and  direction  of  the  rota- 
tion of  the  plane  of  polarised 
light.  They  consist  essentially 
of  a  Nicol's  prism  as  polariser, 
a  tube  carrying  the  substance  to 
be  tested,  and  a  second  Nicol's 
prism  or  analyser,  by  which  the 
extent  of  rotation  is  measured. 
In  all  forms  some  condition  of  the  field  of  vision  is  fixed 


FIG.  7. 


20  ORGANIC    CHEMISTRY. 

upon  as  the  zero  point,  and  the  rotation  of  the  analyser  or 
other  manipulation  necessary  to  restore  this  standard  field 
affords  the  measurement  of  the  rotation  caused  by  the  inter- 
posed substance.  Several  types  of  instrument  have  been 
devised,  of  which  two  are  most  important.  In  one  form, 
devised  by  Soleil,  white  light  is  used  and  a  colored  field, 
known  as  the  transition  tint,  is  taken  as  the  zero  point.  In 
the  other  type  white  light  or  monochromatic  (yellow)  light 
is  used  and  the  zero  point  determined  by  equalising  the 
brightness  of  the  field.  Instruments  of  the  first  form  are 
unsatisfactory  by  reason  of  the  difference  in  susceptibility 
in  the  eyes  of  different  persons  to  color-contrasts.  The 
instruments  of  the  second  type,  commonly  designated 
shadow  instruments  (more  correctly  "penumbral")  are 
now  more  generally  employed;  they  have  been  brought 
of  late  years  to  a  high  degree  of  accuracy  and  conve- 
nience. 

In  the  Laurent  apparatus,  shown  in  Fig.  8,  the  mono- 
chromatic light  passes  through  the  collimating  lens  A  and  is 
polarised  by  the  Nicol's  prism  B,  which  is  so  placed  that  it 
may  be  moved,  on  its  axis,  over  a  small  arc  by  means  of  the 
lever  C  and  clamped  at  any  point ;  by  this  the  brightness 
of  the  field  may  be  varied  and  the  sensitiveness  of  the  in- 
strument increased  or  diminished  as  may  be  needed.  The 
polarised  beam  then  passes  through  a  quartz  plate  of  even 
thickness,  cut  exactly  parallel  to  the  optic  axis,  and  placed 
so  that  it  covers  a  semicircle  of  the  field.  At  the  other  end 
of  the  apparatus  is  the  analysing  prism  E  and  the  eye- 
piece F  fixed  to  a  graduated  disk.  This  combination  can 
be  rotated  upon  its  axis  in  a  complete  circle.  Attached 
arms  carry  view-lenses  for  reading  the  angle  of  rotation, 
and.  the  instrument  is  set  at  zero  by  an  independent  ad- 
justment by  which  the  analysing  prism  is  rotated  without 


PRINCIPLES. 


21 


disturbing  the  position  of  the  graduated  disk.  Ver- 
niers are  provided  for  close  measurement.  The  monochro- 
matic light  must  be  obtained  from  a  sodium  flame,  since 
the  thickness  of  the  quartz  plate  is  adjusted  to  these  rays. 
In  use,  the  tube  is  filled  with  water,  the  instrument 
directed  to  the  source  of  light,  and  the  adjusting  milled  head 
turned  until  the  disk  is  set  at  zero.  The  two  portions  of  the 


FIG.  8. 

field  should  now  appear  equally  illuminated.  If  this  is  not 
the  case,  the  position  of  the  analyser  must  be  altered  by 
means  of  the  independent  adjustment,  the  index  remaining 
undisturbed  at  the  zero  point. 

The  tube  is  filled  with  the  liquid  to  be  tested  and  again 
placed  in  the  instrument.  If  optically  active,  the  plane  of 
the  polarised  light  will  be  rotated  and  one-half  of  the  field 


22  ORGANIC    CHEMISTRY. 

of  observation  will  appear  darker.  The  extent  of  rotation, 
which  will  depend  upon  the  nature  of  the  substance  and  its 
amount,  is  measured  by  rotating  the  analyser  to  the  right  or 
left,  as  the  case  may  be,  until  the  halves  of  the  field  become 
equally  illuminated. 

This  form  of  instrument  can  be  employed  to  measure 
the  rotatory  power  of  all  classes  of  substances,  but  other 
forms  give  accurate  indications  only  with  substances 
which  have  the  same  dispersive  power  as  quartz,  unless 
monochromatic  light  be  used.  In  the  Schmidt  and 
Hansch  penumbral  instrument  the  division  of  the  field  is 
obtained  by  a  special  construction  of  the  polarising  prism 
and  the  restoration  is  accomplished  by  the  adjustment  of 
compensating  quartz-wedges  constructed  so  as  to  produce 
in  the  zero  position  no  rotation.  When  an  optically  active 
substance  is  interposed  in  the  path  of  the  ray,  one  of  the 
quartz-wedges  must  be  moved  to  an  extent  sufficient  to 
overcome  this  rotation  in  order  to  restore  the  standard  field. 
The  effect  is  dependent  upon  the  fact  that  by  this  move- 
ment the  thickness  of  the  quartz  is  increased  or  diminished 
until  it  compensates  for  the  rotation  produced  by  the 
solution.  The  extent  of  movement  of  the  quartz  is  regis- 
tered upon  a  linear  scale,  which  is  read  by  means  of  a  lens 
and  vernier.  White  light  is  employed  in  making  the 
observations.  A  form  of  the  Laurent  instrument,  with 
quartz-wedge  compensation,  and  employing  white  light, 
is  made.  An  instrument  has  been  devised  in  which  the 
field  is  divided  vertically  into  three  zones,  the  central  one 
being  a  broad  band.  Duplicate  Nicol  prisms  are  so  ar- 
ranged that  the  lateral  zones  agree  in  tint,  thus  making 
stronger  contrast  with  the  central  zone. 

Specific  Rotatory  Power. — The  specific  rotatory  power 
of  a  substance  is  the  amount  of  rotation,  in  angular  degrees, 


PRINCIPLES.  23 

produced  by  a  solution  containing  i  gram  of  the  sub- 
stance in  i  c.c.  examined  in  a  column  one  decimeter  long. 
It  is  usually  represented  by  the  symbol  [«].  To  indicate 
the  light  employed  in  the  observation,  [«]D  or  [«]j  is  used. 
D  stands  for  light  of  wave  length  corresponding  to  the  D 
line  of  the  solar  spectrum  (sodium  flame)  and  j  (jaune) 
for  the  transition  tint,  which  in  the  case  of  sugar  solutions 
furnishes  results  corresponding  to  the  "mean  yellow 
ray."  It  is  usual  also  to  indicate  in  the  same  symbol  the 
temperature  of  observation;  thus,  [«]2°. 

Under  ordinary  methods  of  observation  the  specific  rota- 
tory power  is  represented  by  the  following  formula: 

r  -,  100  a       -          i  •    1 

[a]D  =    — —  ;    in  which 

[«]D  is  the  specific  rotatory  power  for  the  light  of  the  sodium  flame, 
a  is  the  angular  rotation  observed, 

c  is  the  concentration  expressed  in  grams  per  100  c.c.  of  liquid, 
/  is  the  length  of  the  tube  in  decimeters. 


24  ORGANIC    CHEMISTRY. 


DERIVATIVES  AND  SYNTHETIC  COMPOUNDS. 

The  list  of  substances  designated  organic  is  increased  by 
transformation  of  natural  compounds  and  by  formation  of 
compounds  from  simpler  bodies  or  elements.  The  latter 
method  is  called  "synthesis." 

Transformations. — Many  methods  are  known.  The  fol- 
lowing are  of  frequent  use: 

HEAT. — Many  organic  bodies  melt  at  a  moderate  heat 
and  at  a  higher  point  volatilise  unchanged.  The  effect  is 
usually  termed  distillation  if  the  substance  is  a  liquid,  and 
sublimation  if  a  solid.  Some  substances  can  be  melted 
but  not  volatilised  except  by  decomposition;  a  few  pass 
apparently  directly  from  the  solid  to  the  gaseous  condition. 
When  a  high  heat  is  applied  many  organic  bodies  undergo 
irregular  decomposition  by  which  a  mixture  of  new  com- 
pounds is  obtained,  none  of  the  original  body  distilling. 
This  is  termed  " destructive  distillation."  It  is  applied 
largely  to  wood  and  natural  bituminous  substances  (coal 
and  shale),  and  is  the  source  of  many  valuable  compounds. 

Destructive  distillation  may  be  illustrated  by  heating  a  few 
pieces  of  wood  or  a  fragment  of  soft  coal  in  a  small  testtube.  Com- 
bustible vapors  are  given  off  and  tar  is  deposited  on  the  cooler 
part  of  the  tube,  If  a  few  fragments  of  bone  or  glue  be  heated, 
offensive  vapors  will  be  emitted,  due  principally  to  the  nitrogen 
compounds  present. 

The  extent  of  decomposition  and  the  substances  formed 
in  destructive  distillation  being  dependent  on  several  condi- 
tions, no  general  reaction  can  be  given.  In  a  few  instances 


DERIVATIVES    AND    SYNTHETIC    COMPOUNDS.  25 

the  action  is  definite.     When  pyrotartaric  acid  is  heated 
for  some  time  above  200°,  it  decomposes  as  follows: 

Pyrotartaric  acid  Butyric  acid  Carbon  dioxide. 

C5H804  C4H802          +          C02 

OXYGEN. — Most  organic  bodies  when  exposed  to  the 
action  of  oxygen  at  high  temperature  burn,  the  carbon 
forming  carbon  dioxide  and  the  hydrogen  forming  water. 
Nitrogen  may  be  liberated  in  the  free  state  or  in  the  form 
of  hydrogen  compounds.  Sulphur  and  phosphorus  are 
oxidised.  At  low  temperatures,  free  oxygen  acts  on  but 
few  substances,  but  by  the  use  of  oxidising  agents  different 
effects  may  be  obtained  according  to  the  conditions  of  the 
action.  Oxygen  may  be  added  to  the  molecule,  hydro- 
gen may  be  removed  without  addition  of  oxygen,  or  oxygen 
may  be  substituted  for  hydrogen  in  the  proportion  of 
O  for  H2.  The  following  reactions  illustrate  these  actions: 

Alcohol  Aldehyde. 

C2H6O  +  O  C2H4O  +  H2O 

Aldehyde  Acetic  acid. 

C2H40  +  O  C2H402 

Alcohol  Acetic  Acid. 

C2H60  +  02  C2H402  +  H20 

Whether  aldehyde  or  acetic  acid  is  formed  in  one  reaction 
from  alcohol,  depends  on  the  energy  of  the  oxidising  agent. 

SO-CALLED  NATURAL  CHANGES. — The  principal  of  these 
are  Fermentation,  Putrefaction  and  Decay. 

FERMENTATION  and  PUTREFACTION,  are  processes  by 
which  organic  bodies  are  converted  into  new  substances 
simpler  in  composition.  They  are  dependent  on  the  action 
of  minute  organisms  and  enzyms.  Substances  that  pre- 
vent these  actions  are  called  antizymotics . 

Some  important  forms  of  fermentation  are: 


26  ORGANIC    CHEMISTRY. 

1.  The  Vinous,  producing   alcohol,  C2H6O,  and    carbon 
dioxide,  CO2. 

2.  The  Acetous,  producing  chiefly  acetic  acid,  C2H4O2. 

3.  The  Lactic,  producing  chiefly  lactic  acid,  C3H6O3. 

4.  The  Butyric,  producing  chiefly  butyric  acid,  C4H8O2. 
Each  fermentation  is  dependent  upon  and  produced  by 

special  enzyrns,  which  are  often  the  products  of  particular 
forms  of  microorganisms. 

PUTREFACTION  is  usually  limited  to  changes  in  nitrog- 
enous bodies.  The  more  complex  forms  of  these  contain 
sulphur  and  phosphorus,  which  are  converted  into  gaseous 
compounds  of  offensive  odors. 

These  transformations  are  largely  by  hydrolysis,  but 
other  actions ,  especially  oxidation ,  occur .  The  products  will 
differ  according  as  the  action  occurs  in  the  presence  of  air 
(aerobic)  or  out  of  contact  of  air  (anaerobic).  Substances 
that  prevent  the  growth  of  microorganisms  or  the  action  of 
their  enzyms  will  prevent  putrefaction  and  are  termed 
antiseptics. 

DECAY. — This  is  the  decomposition  of  organic  bodies  by 
the  slow  action  of  oxygen.  It  takes  place  too  slowly  for 
any  increase  of  temperature  to  be  noticed,  and  it  is  rarely 
complete,  that  is,  some  portions  of  the  elements  escape 
action.  When  wood  burns  with  a  flame  it  leaves  nothing 
but  the  incombustible  mineral  matter  or  ash,  but  when 
it  decays  a  brown  powder  is  left,  which  contains  some  of  the 
original  carbon  and  hydrogen.  Decay  requires  the  access 
of  air,  the  presence  of  moisture  and  a  temperature  above 
the  freezing  point. 

HYDROLYSIS. — This  term  is  applied  to  transformations 
accompanied  by  the  taking  up  of  water  with  production 
of  one  or  more  substances,  in  which  neither  water  nor  the 
original  body  remains.  It  is  brought  about  by  action  of 


DERIVATIVES    AND    SYNTHETIC    COMPOUNDS.  27 

enzyms,  dilute  acids  or  acid  salts.  The  manner  in  which 
the  hydrolysing  body  acts  is  not  understood;  it  is  usually 
not  permanently  affected  by  the  reaction  that  it  produces. 
These  reactions  take  place  only  in  the  presence  of  excess  of 
water,  but  usually  the  equation  is  written  without  the 
hydrolysing  agent  or  the  excess  of  water,  since  these  are 
unchanged.  Thus,  the  hydrolysis  of  cane  sugar  is  written 

C12H22On   +  H20   ==  2C6H1206 

although  the  hydrolysing  agent  and  much  additional  water 
are  present. 

DEHYDROLYSING  AGENTS. — These  are  commonly  called 
dehydrating  agents,  but  the  latter  term  should  be  applied 
only  to  substances  that  remove  water  existing  as  such  from 
other  bodies.  Anhydrous  copper  sulphate  and  calcium 
chloride,  for  example,  are  used  in  the  preparation  of 
absolute  alcohol  to  remove  the  small  amount  of  admixed 
water  that  cannot  be  removed  by  distillation.  The  true 
dehydrolysing  agents  (many  of  which  are  also  dehydrating 
agents)  remove  hydrogen  and  oxygen  in  the  proportion  of 
H2  to  O,  and  form  water,  although  the  water-molecule  does 
not  exist  in  the  original  substance.  In  many  cases  an 
intermediate  combination  is  produced  that  breaks  up 
yielding  water.  For  an  illustration  of  this,  see  the  process 
for  making  ether. 

When  cane  sugar  is  mixed  with  strong  sulphuric  acid, 
water  is  formed,  which  unites  with  the  acid,  and  carbon  is 
set  free.  Among  the  most  used  dehydrolysing  agents  are 
sulphuric  acid,  phosphoric  anhydride  and  zinc  chloride. 
Heat  often  acts  as  a  dehydrolysing  as  well  as  a  dehydrating 
agent. 

NITRIC  ACID. — The  action  of  this  differs  with  the  tem- 
perature and  degree  of  concentration.  When  strong  cold 


28  ORGANIC    CHEMISTRY. 

acid  is  used,  a  substitution  of  NO2  for  H  usually  occurs, 
producing  " nit ro -compounds."  When  the  acid  is  weak 
or  hot  a  direct  addition  of  oxygen  may  take  place,  accord- 
ing to  methods  noted  in  a  preceding  paragraph.  An 
illustrative  reaction  of  the  formation  of  nitro-com- 
pounds  is: 

C6H6   +   HN03    =  C6H5N02   +   H2O 

CHLORINE,  BROMINE  AND  IODINE. — These  sometimes 
form  compounds  by  addition,  but  more  frequently  sub- 
stitute hydrogen  or  other  monads.  In  structural  formulas, 
they  are  generally  in  direct  association  with  carbon.  The 
following  are  illustrative  reactions  for  additive  and  sub- 
stitutive  actions: 

Additive  Benzene  dichloride. 

C6H6    +    C12          =  C6H6C12 

Substitutive  Dichlorbenzene. 

C6H6   +   C14        =       C6H4C12   +   2HC1 

SODIUM  AND  POTASSIUM. — These  expel  hydrogen,  atom 
for  atom,  when  it  is  in  the  hydroxyl  position.  An  illus- 
trative reaction  is : 

Alcohol  Sodium  ethylate. 

C2H5HO    +    Na        =       C2H5NaO    +   H 

SULPHURIC  ACID. — The  action  of  this  as  a  dehydrolysing 
agent,  in  which  respect  it  is  very  powerful,  has  already 
been  noted.  Acting  on  bodies  that  contain  no  oxygen  or 
closed-chain  compounds,  with  or  without  oxygen,  sulphuric 
acid  displaces  an  atom  of  hydrogen  by  substituting  the 
molecular  residue,  HSO3  forming  a  molecule  of  water  at  the 
same  time.  The  substitutions  thus  obtained  are  termed 


DERIVATIVES    AND  SYNTHETIC    COMPOUNDS.                 29 

"sulphonic    acids."     The  following    reaction    illustrates 
their  formation: 

Benzene  Benzene  sulphonic  acid. 

C6H6  +   H2S04  =         C6H5HS03  +   H2O 


By  duplication  of  the  reaction,  poly  sulphonic  acids 
(di,  tri,  etc.)  may  be  obtained.  In  many  cases  sulphuric 
acid  exchanges  one  or  both  of  its  hydrogen  atoms  for 
hydrocarbon  radicles,  producing  esters. 

Dilute  sulphuric  acid  often  produces  hydrolysis,  being 
itself  unaffected  by  the  reaction. 

FRACTIONAL  DISTILLATION. — When  a  liquid  contains  two 
or  more  substances  of  different  boiling  points,  a  partial 
separation  of  these  may  be  made  by  distillation,  changing 
the  receiver  from  time  to  time.  Each  liquid  distils  over 
at  about  its  boiling  point.  The  most  volatile  constituent 
distils  first  and  as  each  constituent  passes  off,  a  thermom- 
eter immersed  in  the  vapor  shows  steadily  rising  tempera- 
ture. The  separate  portions  are  termed  fractions.  It  is 
usually  not  possible  to  separate  compounds  completely  by 
this  method.  The  adhesion  between  liquids  and  vapors 
causes  some  of  the  material  of  higher  boiling  point  to  be 
carried  over  at  a  lower  temperature.  Thus,  a  mixture  of 
common  alcohol  and  water  can  be  distilled  so  as  to  reduce 
the  amount  of  water  to  about  5  per  cent,  of  the  distillate, 
but  absolute  alcohol  cannot  be  so  obtained. 

Fractional  distillation  is  largely  used  in  the  separation 
of  the  hydrocarbons  of  petroleum  and  coal-tar. 

LIGHT  AND  ELECTRICITY. — Many  organic  bodies  are 
affected  by  light,  but  the  action  is  usually  superficial  un- 
less fresh  portions  are  constantly  exposed.  A  mixture  of 
gelatin  and  potassium  dichromate  is  rendered  insoluble, 


30  ORGANIC    CHEMISTRY. 

and  commercial  betanaphthol  is  slowly  darkened  by  light. 
The  other  forms  of  radioactivity  probably  also  cause 
changes. 

Electricity  produces  combination  and  decomposition  of 
organic  bodies.  Electrolysis  can  be  obtained  with  many 
compounds.  By  passing  continuous  or  interrupted 
discharges  from  carbon  poles  in  contact  with  some  gases 
synthetic  actions  may  be  obtained. 


STRUCTURE  OF  ORGANIC  MOLECULES. 

Percentage  Composition  and  Formula. — The  com- 
position of  any  substance  may  be  expressed  without  use 
of  symbols,  or  indication  of  the  number  of  atoms  of 
the  elements  present.  The  parts  by  weight  of  each  ele- 
ment contained  in  one  Hundred  parts  of  the  substance  may 
be  given.  The  composition  of  ordinary  sugar  may  be 
stated  as: 

Carbon 42.1 

Hydrogen    6.4 

Oxygen 51.5 


These  figures  represent  percentage  composition. 

Such  methods  of  expression,  though  simple  and  repre- 
senting facts  alone,  are  not  convenient.  No  satisfactory 
comparison  as  to  the  composition  of  different  compounds 
can  be  reached  except  by  the  construction  of  formulas 
in  which  the  elements  are  represented  by  the  relative 
numbers  of  atoms  probably  present. 

By  dividing  each  figure  by  the  atomic  weight  of  the 
element,  and  clearing  of  fractions,  as  nearly  as  can  be  done 


MOLECULAR    STRUCTURE.  31 

conveniently,  the  number  of  atoms  of  each  element  will 
be  obtained.     For  example: 

42.11    -v-    12    =    3.51    X    3-4    =    n-93 

6.43    -r-      i    =   6.43    X    3-4    =    21.8 
51.56    -T-    16    =    3.24    X    3-4    =    ii. 01 

The  last  column  indicates  the  formula,  C12H22On;  that 
is,  this  formula,  when  calculated  to  percentage  composi- 
tion, will  give  figures  practically  identical  with  those 
actually  obtained  by  analysis  of  a  sample  of  cane  sugar. 

It  is  evident  that  any  multiple  of  this  formula  would 
also  correspond  to  the  percentage  composition,  hence  it  is 
necessary  to  fix  the  numbers  more  rigidly.  The  lowest 
term  is  by  no  means  always  the  proper  formula.  The 
following  list  exemplifies  this.  Each  formula  is  correct 
only  for  the  body  indicated;  a  multiplication  or  division 
of  it  is  inaccurate. 

Molecular  weight. 

Formaldehyde CH2O  30 

Acetic  acid   C2H4O2  60 

Lactic  acid C3H6O3  90 

Tetrose C4H8O4  120 

Arabinose C5H10O5  150 

Dextrose C6H12O6 180 

Mannoheptose C7H14O7  210 

The  formula  is  fixed  in  each  case  by  the  molecular 
weight.  The  determination  of  this  becomes,  therefore,  an 
important  matter.  Several  methods  are  in  use :  among  the 
most  frequently  employed  are  determinations  of  vapor 
density,  freezing  point  of  solution  and  combining  weight. 
The  procedures  for  the  first  two  are  described  in  connec- 
tion with  determination  of  physico-chemical  data. 

Vapor  Density. — This  method  of  ascertaining  molecular 
weight  is  of  wide  application  and  great  value.  Its  use 


32  ORGANIC    CHEMISTRY. 

depends  upon  the  fact  that  when  a  substance  is  capable 
of  volatilising  without  decomposition,  the  density  of  its 
vapor  compared  to  hydrogen  as  unity  will  be  half  the 
molecular  weight. 

For  example:  One  liter  of  vapor  of  common  ether  is 
37  times  as  heavy  at  i  liter  of  hydrogen  gas,  the  conditions 
of  temperature  and  pressure  being  the  same.  The  molec- 
ular weight  of  ether  will  be,  therefore,  74.  This  corre- 
sponds to  the  formula  C4H10O.  (C4=48;  H10=io;  O  =  i6 
=  74).  No  multiple  of  this  formula  will  correspond  to  the 
observed  vapor-density.  The  further  elucidation  of  this 
formula,  expressing  its  rational  form  (C2H5)2O,  is  attained 
by  other  methods. 

All  the  members  of  the  homologous  series  of  hydrocar- 
bons, beginning  with  CH2,  have  the  same  percentage 
composition,  their  formulas  being  multiples  of  the  lowest 
formula,  but  the  vapor  densities  steadily  increase  as  shown 
in  the  annexed  table  (CH2  has  not  been  obtained). 


Formula. 

C2H4    .  .  . 

Density. 
14 

Molecular  weight. 
28 

2  I 

42 

C.Ho 

.  .  ..  28 

S6 

r<» 

70 

The  exact  formula  of  each  member  of  the  series  can 
be  fixed  by  a  determination  of  the  molecular  weight. 

Many  organic  bodies  are  decomposed  by  heat  and  their 
vapor  density  cannot  be  obtained. 

Freezing  Point  of  Solution. — The  general  rule  is  that 
when  different  substances  are  dissolved  in  amount  propor- 
tional to  their  molecular  weights  in  separate  portions  of  the 
same  solvent,  the  depression  of  the  freezing  point  is  the 
same.  Experiment  has  shown  that  if  the  dissolved 


MOLECULAR    STRUCTURE.  33 

substance  and  the  solvent  are  in  the  ratio  of  i  molecule 
of  the  former  to  TOO  molecules  of  the  latter  the  depression 
of  the  freezing  point  of  the  solvent  will  be  0.62°.  The 
method  is  not  widely  applicable,  being  satisfactory  only 
with  substances  of  low  chemical  activity.  Active  bodies, 
such  as  acids,  bases  or  salts,  give  abnormal  results. 

Combining  Weight. — If  an  organic  body  forms  a  definite 
compound  with  any  element  or  with  any  compound,  the 
molecular  weight  of  which  is  known,  such  combination  can 
be  utilized  in  determining  the  molecular  weight.  For 
example,  silver  oxide  reacts  with  acetic  acid  to  form 
silver  acetate  and  water.  Silver  acetate  has  the  per- 
centage composition: 

Silver 64.6 

Carbon 14.4 

Hydrogen    1.8 

Oxygen    19.2 


Proceeding  as  indicated  on  page  31,  that  is,  dividing 
each  percentage  by  the  corresponding  atomic  weight  and 
multiplying  these  quotients  by  a  number  which  will 
practically  eliminate  fractions  (in  this  case  1.66),  the 
following  figures  are  obtained: 

64.6  -f-  108  =  0.6  X  1.66  =  Q-99 

14.4  -7-  12  =  1.2  X  1.66  =  1.99 

1.8  -r-  i  =  1.8  X  1.66  =  2.98 

19.2  -T-  16  =  1.2  X  1.66  =  1.99 

The  ratio  of  the  numbers  in  the  last  column  is  sub- 
stantially 1:2:3:2,  hence  the  formula  of  silver  acetate  is 
AgC2H3O2.     Here,  as  in  the  instance  explained  on  page  31, 
any   multiple   of   the   formula,   for   example,    Ag2C4H6O4, 
3 


34  ORGANIC    CHEMISTRY. 

would  satisfy  the  percentage  composition.  This  uncer- 
tainty is  eliminated  by  determining  the  degree  of  basic 
power  of  acetic  acid.  If  it  is  a  monobasic  acid  silver 
acetate  will  have  but  one  atom  of  silver;  if  a  dibasic 
acid  then  the  'salt  will  have  two  atoms  of  silver.  Ex- 
periment shows  that  acetic  acid  forms  but  one  series  of 
salts,  hence  silver  acetate  must  be  AgC2H3O2,  and  acetic 
acid  C2H4O2.  The  latter  formula  can  be  confirmed  by  a 
determination  of  the  vapor  density. 

Several  other  methods  for  determining  molecular 
weight  are  known,  but  do  not  need  description  here. 
Many  organic  bodies  exist  to  which  no  known  method  is 
applicable;  hence  the  formula  is  not  definitely  assigned. 
Starch,  for  example,  has  a  percentage  composition  corre- 
sponding to  the  ratio  C6H10O5,  but  the  molecular  weight 
cannot  be  ascertained  by  any  of  the  methods  available. 
The  origin  and  transformations  of  starch  suggest  complex 
structure;  it  is  probable  that  C60H100O50  is  an  approxima- 
tion to  its  formula.  In  such  cases  the  formula  is  often 
expressed  in  the  lowest  terms  with  a  provisional  indefinite 
coefficient,  thus  wC6H10O5. 

Empirical,  Rational  and  Structural  Formulas. — The  for- 
mulation of  organic  molecules  -is  based  upon  the  as- 
sumption that  the  valencies  of  the  principal  elements  are 
not  subject  to  irregularity.  Carbon  is  always  taken  as  a 
tetrad,  hydrogen  as  a  monad,  oxygen  as  a  dyad  and 
nitrogen  as  either  triad  or  pentad.  Phosphorus  is  usually 
considered  as  a  pentad;  sulphur  as  either  a  dyad  or  hexad. 
It  is,  however,  freely  assumed  that  polyvalent  elements 
may  combine  by  more  than  one  bond  to  another  atom, 
even  another  of  the  same  nature.  Thus  carbon  is  as- 
sumed to  be  capable  of  forming  the  groups: 
=C— C=  =  C  =  C  =  — C-C— 


MOLECULAR    STRUCTURE.  35 

Oxygen  is  frequently  represented  as  combining  by  both 
its  bonds,  as  in  the  group:  H-O-C  =  O.  The  double  and 
triple  linkings  are  often  termed  "unsaturated." 

It  must  not  be  supposed  that  a  linking  by  two  bonds 
is  a  stronger  union  than  by  one  bond.  Valency  is  a 
standard  of  capacity  of  affinity,  not  of  intensity;  in  fact, 
acetylene  which  is  supposed  to  contain  the  triple  linking 
is  more  easily  decomposed  than  ethane  in  which  the  single 
linking  is  assumed. 

H    H 


H— C=C— H  H— C— C— H 

I       I 
H    H 

Acetylene  Ethaoe 


Some  recent  researches  have  shown  the  existence  of 
compounds  in  which  carbon  is  apparently  a  triad,  and 
others  in  which  oxygen  is  apparently  a  tetrad,  but  the 
theories  in  regard  to  valency  are  provisional  only.  For 
the  great  majority  of  organic  compounds,  the  valencies 
noted  above  are  satisfactory. 

A  formula  that  shows  only  the  number  of  atoms  of  each 
element  in  the  compound  is  an  empirical  formula;  if 
any  supposed  arrangement  is  exhibited  the  formula  is 
termed  rational.  When  the  symbols  are  displayed  so 
as  to  indicate  probable  relations  of  the  atoms  to  each  other 
the  formula  is  termed  structural  (sometimes  graphic}.  The 
following  formulas  exemplify  these  terms : 

Empirical.  Rational.  Structural. 

H    H 

C2H(1O  C2H5HO  H— C— C— O—H 

-I       I 
H    H 


36  ORGANIC    CHEMISTRY. 

Some  authorities  distinguish  between  empirical  and 
molecular  formulas,  applying  the  former  term  to  the  sim- 
plest formula  that  corresponds  to  the  percentage  composi-  ' 
tion,  and  the  latter  term  to  formulas  that  correspond  to 
the  molecular  weight.  Under  this  distinction,  CH2O  would 
be  the  empirical  formula  of  all  the  bodies  in  the  list  on 
page  31  and  would  be  the  molecular  formula  of  formalde- 
hyde only.  In  this  work,  the  terms  will  be  used  synony- 
mously. 

In  some  substances  the  atoms  are  subject  to  changes  of 
position  without  altering  the  identity  of  the  substance. 
Thus  phloroglucol,  C6H6O3,  can  be  represented  by  either 
of  the  following  formulas : 


Symmetric  trihydroxybenzene.  Triketohexamethene. 

C6H3(HO)3  (CH2)S(CO), 

Molecules  that  exhibit  this  variability  are  termed 
tautomeric  or,  rarely,  desmotropic. 

A  general  formula  is  an  algebraic  expression  for  repre- 
senting the  formulas  of  a  group  of  bodies,  for  illustration 
of  which  see  "Homologous  Series." 

Ordinary  structural  formulas  represent  the  atoms 
arranged  upon  the  same  plane,  but  as  molecules  occupy 
space  it  is  desirable  to  formulate  them  on  a  three-dimen- 
sional system.  As  a  basis  for  this,  the  carbon  atom  is 
represented  as  a  tetrahedron.  It  is  not  assumed  that  this 
is  the  shape  of  the  atom,  but  the  four  apexes  of  this  solid 
correspond  to  the  four  valencies  usually  manifested  by 
carbon.  Such  formulas  are  termed  " sfereochemic"  They 
are  most  satisfactorily  shown  by  models,  but  the  annexed 
figures  show  the  usual  methods  of  exhibiting  them. 


MOLECULAR    STRUCTURE. 

OH  OH 


37 


cojr 


OH 

LH 

A 


Dextrolactic  acid 


OH 
I 
.       C— II 

A 

HOOC   CH3 
Levolactic  acid 


Union  of  carbon  atoms  by  two  bonds  is  shown  by  join- 
ing the  tetrahedrons  by  edges  (see  page  40) ;  union  by 
three  bonds,  by  joining  them  by  faces. 

Optical  Activity.  Asymmetric  Atoms. — Optical  activ- 
ity is  the  power  to  rotate  polarised  light.  It  is  possessed 
by  many  bodies,  but  in  organic  chemistry  is  of  importance 
only  when  exhibited  by  substances  in  liquid  form,  by 
fusion  or  solution.  The  rotation  may  be  either  to  the 
right  or  left.  Substances  exhibiting  the  former  action  are 
termed  dextrorotatory,  indicated  by  +  or  d;  substances 
showing  left-handed  rotation  are  termed  levo-  (laevo) 
rotatory,  indicated  by  —  or  1. 

Asymmetric  Atoms. — Any  atom  that  has  each  of  its 
bonds  united  to  an  atom  or  molecule  of  different  nature  is 
asymmetric.  Asymmetric  carbon  is  the  most  important 
example.  In  structural  formulas,  it  will  be  indicated  by 
an  italic  symbol.  (See,  for  example,  the  formula  of  tar- 
taric  acid,  page  88.) 

A  general  relation  exists  between  this  position  of  the 
carbon  atom  and  the  optical  activity,  expressed  by  the  rule 


38  ORGANIC    CHEMISTRY. 

that  "every  carbon  compound  that,  in  the  liquid  con- 
dition, rotates  polarised  light,  will  have  in  its  molecule  at 
least  one  atom  of  asymmetric  carbon."  The  reverse 
of  the  proposition  is  not  true.  Asymmetric  carbon  may  be 
present  in  substances  that  do  not  rotate  polarised  light. 
In  fact,  in  most  cases,  molecules  containing  asymmetric 
carbon  exist  in  three  conditions,  dextro- and  levorotatory, 
and  inactive.  The  inactive  condition  may  depend  upon 
either  the  antagonistic  influence  of  the  asymmetric  carbon 
atoms  within  the  molecule  (neutralisation  by  internal 
compensation)  or  by  the  presence  of  equivalent  quantities 
of  the  opposing  active  substances  (neutralisation  by 
external  compensation). 

The  dibasic  acid  represented  by  the  empirical  formula 
C4H6O6  exists  in  four  forms,  each  of  which  has  the  rational 
formula  H2C2H4O6. 

Ordinary  tartaric  acid ....  Dextrorotatory. 

Levotartaric  "    ...  .Levorotatory. 

Racemic  '    ....  Inactive.      (Mixture  of   +   and  — .) 

Mesotartaric  "    ...  .Inactive.      (Not  a  mixture.) 

In  racemic  acid  the  neutralisation  is  due  to  presence  of 
equivalent  amounts  of  the  +  and  —  forms,  in  mesotartaric 
acid  to  the  existence  of  antagonistic  asymmetric  carbon 
atoms.  The  latter  condition  cannot  exist  in  bodies  having 
but  one  asymmetric  carbon  atom  in  the  molecule.  The 
association  of  molecules  of  opposing  optical  conditions  is 
termed  "racemism." 

Isomerism,  Metamerism  and  Polymerism. — The  proper- 
ties of  bodies  depend  on  the  elements  present  in  them 
and  the  arrangements  of  these  elements  with  respect  to 
each  other.  Different  arrangements  may  be  made  with 
the  same  constituent  atoms,  and  thus  will  arise  bodies 


MOLECULAR    STRUCTURE.  39 

having  the  same  constitution  but  not  identical.  To  all 
such  instances  the  term  isomeric  is  often  applied,  but  it 
is  more  satisfactory  to  limit  it  to  the  instances  in  which 
the  bodies  are  analogous  in  structural  formula.  When 
the  identity  is  in  percentage  composition  and  in  molecular 
weight,  the  structures  being  of  different  types,  the  term 
metameric  is  applicable.  When  the  identity  is  in  percent- 
age composition,  the  molecular  weights  being  multiples, 
but  the  structure  analogous,  the  relation  is  termed  poly- 
meric. True  isomerism  is  often  indicated  by  the  addition 
of  the  prefix  "iso"  to  the  name  of  one  of  the  substances. 
Polymerism  is  sometimes  indicated  by  the  similar  addition 
of  ''para"  to  one  of  the  names.  The  following  illustrations 
will  show  the  application  of  these  principles: 

True  isomerism. 
H — C^N     cyanogen.          C  =  N — H     isocyanogen. 

Metamerism. 
(CH3)2O     methyl  oxide.          C2H5HO     alcohol. 

Polymerism. 
C2H4O     aldehyde.  C6H12O3     paraldehyde. 

Instances  of  isomerism  dependent  on  slight  differences  in 
the  spatial  relation  of  the  constituent  atoms  are  frequently 
observed  in  complex  molecules.  These  can  only  be  shown 
by  stereochemic  formulas.  The  term  "  allo -isomerism" 
proposed  for  this  phase,  has  not  been  generally  adopted, 
the  usual  designation  is  "stereochemic  isomerism."  The 
distinctive  nomenclature  of  these  isomers  is  incomplete. 
One  of  the  methods  is  shown  in  the  annexed  formulas,  in 
each  of  which  a  pair  of  double-linked  carbon  atoms  are 
shown  by  tetrahedrons  joined  by  edges. 


40  ORGANIC    CHEMISTRY. 


Maleic  acid  Fumaric  acid 

Plane  symmetric         Axial  symmetric 
(or  cis-)  form  (or  trans-)  form 

The  syllables  "cis"  and  "trans"  are  used  because,  in  one 
case,  the  similar  radicles  are  on  the  same  side  of  the  carbon 
chain,  in  the  other  case  on  opposite  sides. 

Organic  Radicles. — Any  unsaturated  molecule  may  be 
considered  a  radicle,  and  hence  the  number  of  radicles  in 
the  formula  of  any  body  will  be  limited  only  by  the  number 
of  divisions  that  may  be  assumed.  Many  of  the  groupings 
thus  obtained,  having  no  coherence  or  independent 
function,  are  not  regarded.  Any  grouping  that  confers 
characteristic  properties  or  reactions  upon  the  molecule  or 
that  remains  unchanged  through  a  series  of  reactions, 
is  a  true  radicle.  Some  of  these  are  of  frequent  occurrence, 
are  always  distinguished  in  rational  formulas  and  often* 
indicated  in  the  name  of  the  compound.  The  following 
are  instances: 

HO,  Hydroxyl. — The  hydrogen  of  this  is  easily  replaceable 
by  positive  elements  such  as  potassium  and  sodium. 
When  subjected  to  the  action  of  certain  chlorine  com- 
pounds the  entire  group  is  replaced,  not  the  hydrogen 
alone,  as  occurs  when  hydrogen  is  united  to  carbon.  The 
presence  of  one  or  more  hydroxyl  groups  in  a  compound 
is  often  indicated  by  the  termination  "ol,"  e.g.,  phenol, 
C6H5HO. 

HOCO,  Carboxyl. — This  confers  acid  properties  upon  the 


MOLECULAR    STRUCTURE.  41 

molecule  containing  it.  The  basic  capacity  is  proportional 
to  the  number  of  such  groups  present.  Thus  acetic  acid 
has  but  one  carboxyl  group  and  is  monobasic;  tartaric 
acid  has  two  and  is  dibasic;  citric  acid  has  three  and  is 
tribasic. 

HCO,  Aldehyde  Group. — The  hydrogen  is  joined  to  the 
carbon  atom  and  is  not  replaceable  by  positives.  Com- 
pounds containing  this  group  generally  show  reducing 
power. 

Ketonic  Group. — Carbon  united  to  oxygen  by  two 

bonds  and  by  its  remaining  bonds  to  carbon  atoms  that 
are  not  united  to  a  negative  body.  This  group  generally 
confers  reducing  power  on  the  molecule  containing  it. 

The  foregoing  groups,  it  will  be  noted,  do  not  contain 
asymmetric  carbon  and,  therefore,  do  not  produce  optical 
activity. 

NH2,  Amidogen. — This  generally  confers  capacity  for 
combining  with  acids  which  is  often  proportional  to  the 
number  of  groups  present.  It  is  indicated  by  the  syllables 
"amin"  or  "amid." 

NH,  Imidogen. — This  resembles  in  function  amidogen. 
It  is  indicated  by  the  syllables  "imin"  or  "imid." 

Homologous  Series. — Any  series  of  compounds  in  which 
the  formulas  differ  by  CH2  or  some  multiple  of  this  differ- 
ence by  a  whole  number,  is  termed  a  homologous  series, 
and  the  members  thereof  are  homologues.  These  terms 
are  not  limited  to  hydrocarbons.  The  following  are  exam- 
ples of  homologous  series: 


42  ORGANIC    CHEMISTRY. 

Paraffins.  Alcohols.  Esters. 

CH4    CH3HO (CH3)2SO4 

C2H6 C2H5HO (C2H5)2S04 

C3H8    C3H7HO (C3H7)2S04 

C4H10 C4H9HO (C4H9)2S04 

In  the  third  column  the  constant  difference  is  (CH2)2, 
but  the  series  is  still  homologous.  A  series  intermediate 
between  each  member  is  known,  but  even  if  these  latter 
were  non-existent,  the  homology  would  not  be  lost. 

General  Formulas. — The  existence  of  homologous  series, 
renders  it  possible  to  express  by  one  formula  the  molecule 
of  any  member  of  the  group.  Thus,  in  the  first  series,  the 
atoms  of  hydrogen  are  always  two  more  than  twice  the 
carbon  atoms.  The  general  formula,  CnH2n  +  2,  in  which  n 
represents  any  number  of  atoms,  will  stand  for  any  member 
of  this  series.  If  it  be  required,  for  instance,  to  write  the 
formula  of  the  sixth  member  the  rule  is  simple.  As  the 
carbon  increases  regularly  one  atom  at  a  time,  the  sixth 
member  will  have  C6.  Twice  six  plus  two  is  fourteen; 
the  formula  is,  therefore,  C6H14.  The  general  formula 
of  the  second  series  above  given  is  CnH2n+1HO;  of  the 
third  series  (CnH2n+1)2SO4. 

These  formulas  are  sometimes  used  instead  of  the  series- 
names.  Thus  the  series  beginning  with  CH4  is  often  des- 
ignated as  the  series  CnH2n+2. 

Carbon  Chains. — The  valency  of  each  member  of 
a  homologous  series  is  the  same.  The  explanation  of  this 
is  the  supposition  that,  in  forming  the  molecules,  the  carbon 
has  in  part  satisfied  itself,  so  that  each  atom  of  carbon 
added  carries  into  the  molecule  only  two  degrees  of  valency, 
which  H2  satisfies.  Structural  formulas  will  exemplify 
this  supposition. 


CALIFORNIA   COLLESi 

of    Ph'ARMAPV 

MOLECULAR    STRUCTURE.  43 

Methane,  CH4.  Ethane,  C2H6.  Propane,  C3H8  (tritane). 

H  H    H  H    H    H 

H— C— H      H— C— C— H     H— C— C— C— H 

H  H    H  H     H    H 

These  linked  carbon  atoms  have  been  called,  somewhat 
fancifully,  perhaps,  ''carbon  skeletons."  The  forms  shown 
above  are  termed  "open  chains."  In  other  cases  the 
carbon  is  arranged  in  a  ring  of  three  or  more  atoms  forming 
"  closed  chains  " 

Properties  of  Bodies  in  the  Homologous  Series. — The 
relation  of  homologous  bodies  is  not  a  mere  accidental 
relation  in  formulas.  By  comparing  different  members 
of  the  same  series  analogies  either  in  origin,  .general 
properties,  or  chemical  relations  appear.  The  series 
beginning  with  CH4  is  characterised  by  general  indifference 
to  chemical  action.  The  hydroxides  of  the  series  be- 
ginning with  CH3HO  constitute  a  series  of  alcohols  which 
possesses  specific  physiologic  action.  In  each  series 
fusing  and  boiling  points,  specific  gravity  and  other 
constants  vary  with  considerable  regularity.  The  molec- 
ular weight,  of  course,  increases  regularly. 

Isomeric  Modification  in  Homologous  Series. — Many  or- 
ganic bodies  occur  in  two  or  more  forms  not  sufficiently 
distinct  to  consider  them  as  essentially  different,  and  yet 
not  identical.  In  such  cases,  the  diagrammatic  method 
of  showing  the  linking  of  the  carbon  atoms  may  be  utilised 
to  show  that  the  difference  may  be  due  to  different  positions 
of  the  carbon  atoms,  with  respect  to  each  other  and  to  the 
other  elements  present.  When  the  number  of  carbon 
atoms  is  less  than  four,  fundamental  variation  of  the 


44  ORGANIC    CHEMISTRY. 

structure  is  not  possible,  except  by  closing  the  chain,  as 
shown  below: 


I     I  V 

vith  —  C— C— 


— C — C — C —  is  identical  with  — C — C —  but  not  with        C 

III  'I  A 

-C—  — C-C— 

I  I  I 

With  four  carbon  atoms  two  forms  may  be  obtained, 
as  exemplified  in  the  hydrocarbon,  C4H10: 

H    H    H    H  H    H    H 

I       I       I 
H C— C— C H 

H    H    H    H 


H— C— C— C— C— H  H C— C— C- 

I       I       I       I  III 

H          H 


H— C— H 

A 

Normal  butane  Isobutane  (methyl  propane) 

The  number  of  possible  variations  increases  rapidly 
with  the  number  of  carbon  atoms,  so  that  the  higher 
members  of  the  series  show  numerous  instances.  The 
structural  formulas  given  above  may  be  condensed  as 
follows : 

Normal  butane.  Isobutane. 

CH3CH2CH2CH3  CH3CH(CH3)CH3 

CLASSIFICATION    AND    NOMENCLATURE    OF    ORGANIC 
COMPOUNDS. 

Many  organic  bodies  are,  in  formulas,  structurally 
analogous  to  inorganic  bodies,  and  may  be  classified  and 
named  on  the  same  systems  as  used  in  inorganic  chemistry. 
The  groups  termed  acids,  alkalies  and  salts,  are  well 
represented  in  organic  chemistry.  Oxides,  sulphides  and 
halogen  compounds  are  also  abundant.  The  phenomena 


CLASSIFICATION.  45 

of  isomerism,  polymerism,  tautomerism  and  homology  are 
practically  peculiar  to  organic  chemistry,  and  hence  the 
methods  of  classification  and  nomenclature  must  be  much 
more  elaborate.  Unfortunately  the  systems  of  naming 
and  arranging  organic  compounds  are  still  incomplete  and 
unsatisfactory. 

In  classifying  organic  bodies  it  is  most  convenient  to 
begin  with  the  binary  forms — the  hydrocarbons.  These 
are  very  numerous  and  cannot  be  named  according  to 
their  formulas,  as  is  so  easily  done  with  binary  inorganic 
compounds.  Each  hydrocarbon  has  a  name  referring  to 
some  property,  source,  use  or  other  incidental,  often 
fanciful,  relation. 

Thus  methane,  CH4,  the  fundamental  hydrocarbon  of 
organic  chemistry,  because  the  simplest  of  all  known  ones 
in  structure,  was  called  marsh  gas,  because  it  was  detected 
in  the  emanation  from  the  mud  of  marshes.  The  name, 
methane,  is  due  to  the  relation  of  the  hydrocarbon  to 
methyl  alcohol  and  that  name,  in  turn,  is  really  a  mis- 
nomer, for  it  refers  to  a  Greek  word  meaning  "wine,"  to 
which  methyl  alcohol  has  no  direct  relationship.  Sim- 
ilarly the  hydrocarbon,  butane,  is  so  named  owing  to  its 
structural  relations  to  butyric  acid,  which  is  obtained 
from  butter.  "  Butyric  "  is  derived  from  the  Greek  word 
for  butter. 

Suggestions  have  been  made  to  name  compounds  by 
syllable  systems,  according  to  which  the  elements  should 
be  indicated  by  their  symbols  and  the  number  of  atoms  in 
each  by  the  vowels  in  the  usual  alphabetic  order,  i.  e., 
a  =  i;  e=2,  etc.  By  this  system  CH4  would  be  "Caho." 
These  methods  have  not  received  serious  attention,  as  they 
produce  jargon. 

Nomenclature  in  organic  chemistry  is  in  the  main  based 


46  ORGANIC    CHEMISTRY. 

on  the  principle  that  the  name  shall  show  the  molecular 
structure  or  immediate  relationships  of  the  body.  It  is  not 
usual  to  base  it  on  properties,  but  two  well-marked  in- 
stances of  this  are  to  be  noted.  Nitrogenous  organic  bodies 
termed  "enzyms"  or  "non-organised  ferments"  are 
generally  distinguished  by  the  termination  "ase."  Ni- 
trogenous bases  are  distinguished  by  the  termination 
"ine."  Many  substances  are  as  yet  not  definitely  classi- 
fiable. For  these  the  termination  "in"  is  provisionally 
used. 

The  following  is  a  summary  of  the  principal  groups  of 
organic  bodies: 

Hydrocarbons. 

Ethers,  Alcohols,  Aldehydes,  Ketones,  Esters. 

Oils  and  Fats. 

Acids  and  Salts. 

Carbohydrates. 

Cyanogen  and  derivatives. 

Amine  and  derivatives. 

Alkaloids,  Ptomaines  and  Leucomaines. 

Azo-,  Diazo-  and  Hydrazo-compounds. 

Proteids. 

Enzyms. 

The  distinction  between  the  groups  is  not  well  defined; 
many  bodies  may  be  included  in  more  than  one  group, 
their  molecules  exhibiting  mixed  structure.  Thus  lactic 
acid  has  alcoholic  as  well  as  acidic  structure.  Dextrose 
which  is  classed  among  the  carbohydrates  has  alcoholic 
and  aldehydic  structure. 

Organic  compounds  are  sometimes  divided  into  two 
groups,  termed  respectively: 

(i)  Open-chain  or  aliphatic  compounds,  and  (2)  closed- 


NOMENCLATURE.  47 

chain  or  cyclic  compounds.  This  division  is  also  imper- 
fect, in  that  many  bodies  cannot  be  assigned  positively  to 
either  group. 

Organic  compounds  that  show  analogy  to  inorganic 
compounds  may  be  designated  by  analogous  terms.  Thus, 
the  formula  of  common  alcohol  may  be  written  C2H5HO, 
showing  a  structural  analogy  to  KHO.  C2H5  is  called 
ethyl,  hence  alcohol  is  termed  ethyl  hydroxide. 

To  assist  in  distinguishing  organic  bodies,  many  syllables 
have  been  applied  as  prefixes  or  suffixes.  A  few  examples 
of  the  more  important  will  be  here  given.  Other  less 
important  ones  will  be  mentioned  in  connection  with  the 
compounds  that  exemplify  the  use. 

"Ane,"  "ene,"  "ine,"  "one,"  etc.,  are  used  for  different 
series  of  hydrocarbons.  The  system  may  be  extended  by 
using  other  vowels  and  diphthongs.  In  these  syllables  the 
first  vowel  is  long.  Care  must  be  taken  not  to  confuse 
these  terminations  with  others  apparently  similar,  namely 
"one"  used  to  indicate  a  special  form  of  oxygen  compound, 
called  a  ketone,  and  the  use  of  "ine"  (in  which  "i"  is  short) 
as  a  termination  for  basic  substances. 

"ase"  indicates  an  enzym; 

"ose"  indicates  a  carbohydrate,  but  is  also  applied  to 
some  intermediate  products  of  proteid  hydrolysis; 

"  ol "  indicates  hydroxyl ; 

"  yl "  indicates  a  radicle,  generally  one  of  uneven  valency ; 

"in"  has  no  exact  significance;  it  is  employed  largely 
for  bodies  not  definitely  classifiable.  It  is  used  for  some 
common  enzym,  but  it  would  be  best  to  use  the  proper 
termination  for  these ; 

"al"  indicates  an  aldehyde; 

"mono,"  "di,"  "tri,"  etc.,  are  used  with  analogous 
significance  to  that  in  inorganic  chemistry; 


48  ORGANIC    CHEMISTRY. 

"nitro,"  "chloro,"  "bromo,"  "iodo,"  refer  respectively 
to  the  presence  of  NO2,  Cl,  Br,  I; 

"nitroso"  indicates  the  group  NO; 

"azo"  and  "diazo"  indicate  the  group  — N  =  N — ; 

'  *  hydrazo ' '  indicates  the  group  —  N  —  N  =  ; 

"amin"  or  "amid"  indicates  the  group  NH2; 

"imin"  or  "imid"  indicates  the  group  NH; 

"thio"  indicates  sulphur; 

"sulpho"  is  often  used  instead  of  "thio"; 

"pyro"  is  used  to  indicate  a  body  that  has  been  ob- 
tained by  heat; 

"sulphonic"  indicates  the  group  HSO3;  a  salt  of  this, 
by  replacement  of  H,  is  a  "sulphonate." 


DESCRIPTIVE  CHEMISTRY. 

Aliphatic  or  Open-chain  Hydrocarbons. 

Compounds  of  carbon  and  hydrogen  are  very  numerous. 
Carbon  being  a  tetrad,  the  greatest  number  of  atoms  of 
hydrogen  that  can  combine  with  one  of  carbon  is  four. 
This  compound  CH4,  commonly  known  as  methane,  is 
the  type  of  the  aliphatic  or  open-chain  hydrocarbons;  all 
other  compounds  of  this  class  are  capable  of  being  re- 
garded as  derived  therefrom  by  subtraction  or  substitution, 
or  both. 

Substituting  all  or  part  of  the  hydrogen  in  CH4  by  any 
other  element  or  group  of  elements,  does  not  disturb  the 
saturation;  the  molecule  remains  a  saturated  hydro- 
carbon. Hence  the  compounds  CC14,  CHC13,  CH2C12, 
CH3C1  will  all  be  referable  to  the  same  group  as  CH4. 

By  successive  subtractions  of  H  from  CH4,  are  obtained 
a  series  of  unsaturated  molecules,  known  as  radicles,  the 
valency  of  which  will  be,  in  each  case,  equal  to  the  number 
of  hydrogen  atoms  removed.  CH3  is  a  monad  radicle 
because  it  lacks  one  atom  of  hydrogen;  CH2  is  a  dyad, 
CH  a  triad,  while  C,  of  course,  is  a  tetrad.  From  each  of 
these  molecules — termed  hydrocarbon  radicles — deriva- 
tives may  be  obtained,  comparable  in  the  main  to  similar 
derivatives  from  the  elements  themselves.  Thus  CH3 
forms  a  chloride,  bromide,  hydroxide,  sulphate,  each 
analogous  in  formula  to  the  similar  compound  formed  by 
the  elements  of  the  potassium  group.  CH2  yields  com- 
4  49 


50  ORGANIC    CHEMISTRY. 

pounds  analogous  in  formulas  to  those  from  dyad  metals, 
and  so  on.  In  addition  these  radicles  have  substitution 
power,  that  is,  they  may  replace  the  hydrogen  of  other 
organic  compounds.  Each  of  them  and  each  of  their 
derivatives  is  the  first  member  of  a  homologous  series. 
A  system  of  nomenclature  by  terminations  has  been 
adopted  to  distinguish  the  different  series;  the  vowels  are 
used  in  regular  order,  and  the  syllable  yl  indicates  uneven 
valency.  The  number  of  carbon  atoms  is  indicated, 
except  in  the  first  two  members  of  each  series,  by  syllables 
formed  from  Greek  numerals. 

The  following  table  will  be  sufficient  to  show  the  prin- 
ciple of  the  above  classification : 


Series 

Series 

Series 

Series 

Series 

I 

2 

3 

4 

5 

Gen.  Formula  Gen.  Formula 

Gen.  Formula 

Gen.  Formula 

Gen.  Formula 

CnH2n  +  2 

CnH2n  +  1 

CnH2n 

CnH2n-, 

CnH2l,_2 

ALKYLS 

MONATOMIC 

ALCOHOL  RAD- 

PARAFFINS 

ICLES 

OLEFINS        METHYLENES    ACETYLENES 

Methane 

Methyl 

Methene 

Methenyl 

Methine 

CH4 

CH3 

CH2 

CH 

C 

Ethane 

Ethyl 

Ethene 

Ethenyl 

Acetylene 

C2H6 

C2H. 

C2H4 

C2H3 

(Ethine) 

C2H2 

.  Propane 

Propyl 

Propene 

Propenyl 

Allylene 

(Tritane) 

(Trityl) 

(Tritene) 

(Tritenyl) 

(Propine) 

C3H8 

C3H7 

C3H6 

C3H5 

C3H4 

Butane 

Butyl 

Butene 

Tetrenyl 

(Crotonylene) 

(Tetrane) 

(Tetryl) 

(Tetrene) 

C4H7 

Butine 

C4H10 

C4H9 

C4H8 

C4H6 

Pentane 

Amyl 

Pentene 

Pentenyl 

(Valerylene) 

C5H12 

(Pentyl) 

C5H10 

C5H9 

Pentina 

Hexane 

Hexyl 

Hexene 

Hexenyl 

Hexine 

C6HH 

C6H13 

C6H12 

C6H11 

C6H1Q 

PARAFFIN    OR    METHANE    SERIES.  51 

It  does  not  necessarily  follow  that  all  of  these  bodies 
have  been  obtained,  but  most  of  them  are  known  and  the 
others  could  doubtless  be  prepared.  The  members  of 
each  vertical  column  are  homologous  with  each  other. 

The  members  of  the  first  series  being  saturated  hydro- 
carbons, are  practically  indifferent  to  chemical  reagents. 
Common  paraffin  consists  of  several  of  them,  and  the 
series  has  therefore  been  called  the  "paraffin  series" ;  those 
of  the  second  series;  because  their  compounds  are  on  the 
type  of  the  alkali-metals,  are  termed  "alky Is";  the  mem- 
bers of  the  third  series  have  been  called  olefins,  from  the 
older  name  of  one  of  the  members  of  it. 

PARAFFIN  OR  METHANE  SERIES. 

The  members  of  this  series  are  saturated  molecules  not 
easily  affected  by  chemical  agents.  Many  of  them  are 
found  in  petroleum. 

Methane,  Marsh  Gas,  CH4. — This  is  a  colorless  and  odor- 
less gas  which  is  formed  at  the  bottom  of  marshes  and 
stagnant  pools  (whence  the  name  marsh  gas)  as  the  result 
of  the  slow  hydrolysis  of  cellulose. 

C6H1005  +  H20  =  3CH4  +  3C02 

This  decomposition  is  probably  due  to  the  presence  of 
microorganisms.  The  gas  may  be  collected  by  filling  a 
bottle  completely  with  water,  inserting  a  funnel,  and  stir- 
ring the  decaying  vegetable  matter  in  the  bottom  of  the 
pool  while  holding  the  bottle  and  funnel  in  an  inverted 
position  under  the  surface  of  the  water.  The  bubbles 
which  arise  may  be  guided  through  the  funnel  into  the 
bottle  in  order  to  displace  the  water. 

Methane  is  a  product  of  ordinary  putrefaction  and 
also  results  from  the  slow  decomposition  of  certain  varie- 


52  ORGANIC    CHEMISTRY. 

ties  of  coal.  When  mixed  with  air  it  constitutes  -firedamp 
that  causes  explosions  in  coal  mines.  Coal-gas  manu- 
factured for  illuminating  purposes  consists  of  nearly  50 
per  cent,  of  methane;  the  natural  gas,  largely  used  for 
fuel  and  illuminating  purposes  in  some  parts  of  the  United 
States,  is  almost  pure  methane  (about  90  per  cent.).  Me- 
thane may  be  produced  artificially  in  several  ways:  the 
most  convenient  method  for  experimental  purposes  is  to 
strongly  heat  a  mixture  of  anhydrous  Sodium  acetate,  so- 
dium hydroxide  and  calcium  oxide. 

Experiment  i. — Mix  intimately,  by  rubbing  in  a  mortar,  equal 
parts  of  dried  sodium  acetate  and  quicklime.  Introduce  the 
mixture  into  an  ignition  tube  and  apply  strong  heat.  Methane 
will  be  evolved  and  may  be  ignited  at  the  mouth  of  the  tube.  A 
portion  of  the  gas  may  be  collected  over  water  and  its  explosive 
qualities  tested  after  mixing  it  with  air. 

Ethane,  C2H6,  is  a  colorless  and  odorless  gas,  found  in 
natural  gas  in  small  amounts  and  also  existing  in  crude 
petroleum. 

Propane,  C3H8;  Butane,  C4H10;  Pentane,  C5H12;  Hex- 
ane,  C6H14  and  Heptane,  C7H16,  are  all  found  in  crude 
petroleum. 

Butane  is  more  commonly  known  as  '  *  Cymogene  ' '  and  is 
used  as  an  anesthetic  in  surgery. 

Pentane,  commonly  called  "Rhigolene"  is  used  as  an 
anesthetic  and  solvent.  The  vapor  of  pentane  is  used  as  a 
standard  in  determining  the  illuminating  power  of  gas 
and  electric  lamps. 

Hexane,  commonly  known  as  '"Gasolene,"  is  used  as  a 
solvent  and  for  illuminating  and  heating  purposes. 

The  hydrocarbons  or  petroleum  products  boiling  between 
70°  and  120°  and  having  a  specific  gravity  between 
0.685  and  0.690  are  known  under  the  name  of  "Ligroin." 


PARAFFIN    OR    METHANE    SERIES.  53 

The  use  of  the  terms  benzine,  benzin  and  benzolene  has 
led  to  great  confusion  between  the  petroleum  products  and 
benzene,  C6H6,  (benzol),  the  principal  constituent  of  coal- 
tar  naphtha. 

Heptane  exists  in  petroleum  spirit  and  also  constitutes 
the  greater  portion  of  the  oil  from  Pinus  Sabiniana.  It  is 
used  as  a  solvent  under  the  trade  designation  of  "Abietene." 

Kerosene,  or  Coal  Oil,  is  that  mixture  of  the  hydro- 
carbons which  is  most  suitable  for  burning  in  lamps.  The 
name  kerosene  is  a  contraction  of  keroselain  or  ''wax 
oil"  and  was  originally  a  trade-mark  for  a  certain  fraction 
of  petroleum  oil. 

The  hydrocarbons  from  C16H34  to  C20H42  constitute  the 
various  grades  of  petrolatum.  Some  members  of  the  olefin 
series  are  also  associated  with  the  paraffins  in  these 
compounds.  The  different  consistencies,  colors  and  melt- 
ing-points of  petrolatum  preparations  are  obtained  by 
different  methods  and  represent  varying  degrees  of  puri- 
fication. Commercial  products  not  differing  materially 
from  petrolatum  are  sold  under  various  trade  names,  as 
cosmoline,  vaseline. 

A  mixture  of  hydrocarbons  having  a  higher  melting  point 
than  the  petrolatums  constitutes  the  product  known  as 
paraffin.  The  name  paraffin,  from  parum,  without, 
affinis,  affinity,  has  also  been  applied  to  the  entire  group 
of  saturated  hydrocarbons,  indicating  the  difficulty  of 
inducing  chemical  change.  Common  paraffin  is  a  white, 
waxy  solid,  having  a  melting  point  of  from  45°  to  65° 
and  a  metallic  sound  when  struck.  It  has  an  extensive  use 
as  a  substitute  and  adulterant  for  beeswax  and  spermaceti. 

A  small  amount  of  these  hydrocarbons  is  sufficient  to  form  ex- 
plosive mixtures  with  a  large  volume  of  air.  This  may  be  illus- 
trated by  pouring  a  few  drops  of  one  of  the  volatile  products  into 


54  ORGANIC    CHEMISTRY. 

a  i  oo  c.c.  beaker,  covering  it  with  a  glass  plate,  and,  after  a  few 
minutes,  removing  the  plate  and  applying  a  light. 

Synopsis  of  the  Paraffin  Series. — The  lowest  members  of 
the  series  at  ordinary  temperatures  are  gaseous,  the  inter- 
mediate members  liquid  and  the  higher  members  solid. 
The  boiling  points  rise  with  the  molecular  weights  and  in 
the  higher  members  of  the  series  the  specific  gravities  and 
melting  points  show  a  regular  increase.  The  following 
tables  illustrate  these  facts : 


C3H8         Propane 
C4Hi0       Normal  Butane 

Trimethyl  Methane 
C5H12       Normal  Pentane 

Dimethylethyl  Methane 

Tetramethyl  Methane 
C6H14       Normal  Hexane 

Methyldiethyl  Methane 

Dimethylpropyl  Methane 

Di-isopropyl 

Trimethylethyl  Methane 


Structural  Formula. 
CH3.CH2.CH3 
CH3.CH2.CH2.CH3 
CH3.CH(CH3)2 
CH3.(CH2)3.CH3 
CH3.CH2.CH(CH3)2 
C(CH3)4 
CH3(CH2)4CH3 
CH3(C2H5)2CH 
CH3.CH2.CH2.CH(CH3)2 
(CH3)2.CH.CH.(CH3)2 
CH3.CH2.C(CH3)3 


Melting  Point.  B.  P. 

Heptane C7H16  ...  98.4° 

Octane   C8H18  ...       •  125.5° 

Nonane    C9H20  —  51°  I49-5° 

Decane     C10H22  -32°  g  173° 

Undecane CUH24  —26.5°  g  194.5 

Dodecane C12H26  — 12°  214° 

Tridecane C13H28  -  6.2°  *  234° 

Tetradecane    C14H30  +5-5°  £1252.5° 

Pentadecane C15H32  +  10°  *r  270.5° 

Hexadecane C16H34  +  18°"  fc  287.5° 

Heptadecane C17H36  +22.5°  fc  303° 

Octadecane C18H38  +28°  1  317° 

Nonadecane C18H40  +  32°  P  330° 

Eicosane    C20H42  +  36.7°  «  205° 

Heneicosane    .  .  .  .C21H44  +40.4°  |  215° 

Docosane C22H46  +44.4°  224.5° 

Tricosane C23H48  +  47-7°  *  234° 

Tetracosane C24H50  +51.1°  |  243° 

Heptacosane   .  .  .  .C27H58  +59-5°  2>  27°° 

Hentriacontane  .  .C31H64  +  68.1°  £  302° 

Dotriacontane  .  .  .C32H66  +70.0°  %  310° 

Pentatriacontane.C35H72  +74.7°  5    I  33l0 

Dimyricyl    Q60H122  +  102° 


Boiling  point  below 

760  mm. 

-45°  (B.  27,  3306) 
+  i°  (B.  27,  2768) 
-17° 
+38° 
+30° 
-fio° 
+71° 
+64° 
+62° 
+58° 
+430-48° 

Sp.  Gr. 
0.7006(0°) 
0.7188(0°) 

0.7330(0°) 
0.7456(0°) 


0-773 
0-775 
0-775 
o-775 
0-775 
0.776 
0.776 
o.777 
0-777 
0.778 
0.778 
0.778 
0.778 

0-779 
0.780 
0.781 
0.781 


At  their 
M.  P. 


PARAFFIN    OR    METHANE    SERIES.  55 

DERIVATIVES  OF  THE  PARAFFINS. — Paraffins  are  not 
easily  acted  upon  by  chemical  agents.  Substitution  com- 
pounds may  be  obtained  by  direct  action  of  chlorine  and 
bromine  upon  all  of  them,  and  nitro-compounds  may  also 
be  produced  directly  from  some  of  the  higher  members. 

By  successive  substitution  of  the  hydrogen  in  CH4  four 
derivatives  are  obtained  which  will  serve  as  an  illustration 
of  the  nomenclature  of  this  class  of  compounds. 

Methane CH4 

Monochlormethane  (methyl  chloride) CH3C1 

Dichlormethane  (methene  chloride) CH2C12 

Trichlormethane  (methenyl  chloride) CHC13 

Tetrachlormethane  (carbon  tetrachloride) - .  .  CC14 

The  first  substitution  product,  monochlormethane  or 
methyl  chloride,  CH3C1,  may  be  made  by  the  direct  action 
of  chlorine  on  methane  or  by  the  action  of  hydrochloric 
acid  gas  on  methyl  hydroxide.  It  is  gaseous  at  ordinary 
temperatures  but  is  liquefied  under  a  pressure  of  several 
atmospheres.  This  liquid  is  sometimes  used  to  produce 
local  anesthesia. 

The  second  product,  dichlormethane  or  methylene  chloride, 
CH2C12,  may  be  prepared  by  the  action  of  chlorine  upon 
methane  or  upon  methyl  chloride.  It  is  a  colorless  liquid 
boiling  at  41°  and  has  been  used  as  an  anesthetic. 

The  third  substitution,  trie  hlor  methane ,  is  the  important 
body,  chloroform,  CHC13.  It  may  be  made  by  the  direct 
action  of  chlorine  upon  methane  but  it  is  usually  made  by 
the  action  of  chlorinated  lime  upon  alcohol  or  acetone. 

When  pure  it  is  a  colorless,  fragrant,  mobile,  volatile 
liquid,  sp.  gr.  1.49,  boiling  point  60°,  sparingly  soluble  in 
water,  soluble  in  all  proportions  in  alcohol,  ether,  petro- 
leum spirit  and  fixed  and  volatile  oils.  It  is  not  readily  in- 
flammable, but  vapor  from  boiling  chloroform  burns  with  a 


56  ORGANIC    CHEMISTRY. 

greenish  flame.  It  is  used  in  analytical  chemistry  as  a 
solvent.  It  has  marked  antiseptic  powers.  When  in- 
haled it  produces  deep  anesthesia ;  when  swallowed  it  acts  as 
an  irritant.  Pure  chloroform  is  unstable;  the  commercial 
article  contains  about  i  per  cent,  of  alcohol  which  acts 
as  a  preservative. 

Experiment  2. — Mix  100  grams  of  chlorinated  lime  with  about 
500  c.c.  of  water  in  a  large  flask  provided  with  a  thistle  tube  and 
a  distillation  tube  which  is  connected  with  a  well-cooled  condenser. 
Add  gradually,  through  the  thistle  tube,  about  30  c.c.  of  acetone 
and  apply  a  gentle  heat  until  the  chloroform  begins  to  distil  over, 
when  the  heat  may  be  regulated  according  to  the  rapidity  of  the 
distillation.  Purify  the  chloroform  by  first  washing  it  with  water, 
then  with  a  small  quantity  of  sulphuric  acid,  and  finally  with  a 
solution  of  sodium  carbonate,  after  which  it  may  be  distilled  on 
the  water  bath. 

Instead  of  the  thistle  tube  and  delivery  tube,  the  arrangement 
shown  in  Fig.  57  may  be  used.  The  acetone  is  placed  in  the  stop- 
pered funnel  tube  and  the  addition  of  it  is  easily  controlled.  The 
hemispherical  dish  (the  bowl  of  an  ordinary  water-bath)  contains 
water  heated  gently  by  the  burner.  The  bowl  is  moved  up  so  as 
to  include  the  lower  half  of  the  flask.  Cold  water  passes  through 
the  condenser.  This  arrangement  of  apparatus  is  suitable  for 
many  distillations. 

Carbon  tetrachloride ,  CC14,  is  the  final  result  of  the 
successive  substitution  of  the  hydrogen  of  methane  by 
chlorine.  It  is  a  colorless  liquid  having  an  odor  resembling 
chloroform;  sp.  gr.  1.56.  It  boils  at  68°.  It  is  a  power- 
ful anesthetic  but  is  most  largely  used  at  the  present 
time  as  a  non-inflammable  solvent  in  manufacturing 
and  technical  operations. 

Bromofonn,  CHBr3,  is  analogous  in  composition  to 
chloroform  and  is  used  mainly  as  an  anesthetic. 

lodoform,   CHI3,  is   also   analogous  to   chloroform,   and 


PARAFFIN    OR    METHANE    SERIES.  57 

is  largely  used   as   an   antiseptic  in   surgery.     It   cannot 
be  obtained  by  direct  substitution  of  iodine  in  the  methane 


FIG.  9. 

group,  but  it  is  made  by  the  action  of  iodine  on  alcohol  or 
acetone  in  the  presence  of  an  alkali.  It  has  a  pene-' 
trating,  disagreeable  odor.  It  crystallises  in  bright  yel- 


58  ORGANIC    CHEMISTRY.  • 

low  hexagons  which  are  soluble  in  chloroform,  ether  and 
petroleum  spirit. 

Experiment  3. — Dilute  2  c.c.  of  acetone  to  make  about  10  c.c., 
and  add  a  solution  of  i  gram  of  potassium  iodide  and  i  gram  of 
sodium  hydroxide  dissolved  in  about  5  c.c.  of  water;  then  add 
solution  of  sodium  hypochlorite  drop  by  drop,  observing  the 
separation  of  yellow  crystals  of  iodoform,  which  may  be  collected 
on  a  filter  paper,  dried  and  tested  for  solubility  in  water,  alcohol 
and  ether. 

ALKYLS,  MONATOMIC  ALCOHOL  RADICLE  SERIES. — This 
is  a  series  of  monad  radicles  sometimes  called  the  methyl 
series,  often  the  alcohol  radicles,  because  their  hydroxides 
are  the  common  alcohols.  The  term  alkyls  is  most  con- 
venient. The  following  derivatives  are  obtained  from  this 
series : 

Normal  oxides  called  ETHERS  : 

(CH3)2O,  methyl  ether,  analogous  to  Na2O,  sodium  oxide. 
(C2H5)2O,  ethyl  ether,  analogous  to  Na2O,  sodium  oxide. 

Compounds  with  halogens,  also  sometimes  called  ETHERS  : 

CH3C1,  methyl  chloride,  analogous  to  NaCl,  sodium  chloride. 
C5HnCl,  amyl  chloride,  analogous  to  NaCl,  sodium  chloride. 

Compounds  derived  from  acids  called  ESTERS  or  COM- 
POUND ETHERS: 

C2H5NO2,  ethyl  nitrite,  analogous  to  NaNO2)  sodium  nitrite. 
CsHnCgHgOa,    amyl    acetate,    analogous    to    NaC2H3O2,    sodium 
acetate. 

The  compounds  analogous  to  the  acid  salts  are  some- 
times called  VINIC  ACIDS: 

C2H5HSO4,   sulphethylic    or    sulphovinic    or    ethylsulphuric    acid, 
analogous  to  KHSO4. 


PARAFFIN    OR    METHANE    SERIES.  59 

Hydroxides  called  ALCOHOLS: 

CH3OH,  methyl  alcohol,  analogous  to  KOH,  potassium  hydroxide 
C2H6OH,  ethyl  alcohol. 
CgHnOH,  amyl  alcohol. 

Compounds  containing  two  different  radicles  are  called 
MIXED  ETHERS: 
(CH3)(C2H5)O,  methylethyl  ether. 

Each  compound  here  mentioned  is  a  member  of  a  homol- 
ogous series. 

In  general,  when  alcohols  are  oxidised  by  a  limited 
amount  of  oxygen,  two  atoms  of  hydrogen  are  removed 
and  no  oxygen  is  added.  When  oxidised  in  a  free  supply 
of  oxygen,  an  atom  of  oxygen  takes  the  place  of  the 
removed  hydrogen.  In  this  way  is  obtained: 

Ethyl  alcohol  Ethyl  aldehyde. 

C2H5OH    +   O       =      C2H4O    +   H2O 

Acetic  acid. 

C2H5OH    +    02     =     C2H402    +    H20 

Thus  each  alcohol  or  hydroxide  may  be  made  to  yield 
an  aldehyde  (from  alcohol  dehydrogenatum)  and  an  acid, 
each  of  these  being  one  of  a  homologous  series. 

The  series  of  acids  is  very  important;  many  of  them 
are  obtained  from  fats  and  oils,  hence  have  been  called 
fatty-acids.  The  following  table  gives  an  outline  of 
some  of  the  important  derivatives  of  this  series.  One 
atom  of  the  hydrogen  in  the  acid  is  replaceable  by  any 
positive  element  or  radicle,  so  that  it  is  generally  written 
apart  from  the  other  atoms  as  in  HC2H3O2,  acetic  acid. 
In  this  table  only  a  few  of  the  esters  are  given. 

Isomeric  modifications  are  possible  in  these  bodies, 
except  with  methyl,  ethyl  and  some  of  their  derivatives. 


CD* 

0) 

M 

0 

CD 

o" 

CD 

0 

4-> 
OJ 

eo 

CD 
4J 

Oj 

cf 

CD 

4^ 

'jH 

4\j 

s 

0 

O 
gg 

^ 

'S 

x—  ^ 

*2 

^ 

.15 

^ 

fc 

w 

o 
°« 

*>* 

ffi 

^ 

a| 

js 

sf 

^ 

5? 

5 

^ 

cj9 

4-3 

c? 

a 

c? 

-g 

d5 

| 

0 

1 

2 

PQ 

ACIDS. 

HCOOH 

jd 
1 

CJ 

s 

0 

HH 

M 

0 
0 

OM 
M 

0 

.12 

0) 

0 

M 

0 
0 
o 

K 
OM 

ropionic  acid. 

K 
0 
0 

^d 
1 

W 
ffl 

3 

PM 

CD       . 

CD* 

CD    ^- 

CD* 

TT-J        CD 

• 

_fi  1>^ 

^•gl 

_ri^ 

K^> 

>% 

8 

Q 
>• 

Q 

*&    CD 

q, 

^^ 

0 

^d 

q 

T3 

0 

0 

1 

S 

w 

HH 

13  2 

HH 

13  2 

ffi 

13 

HH 

K 

•i 

Q 

O 

*>>  S 

b 

^H     4J 

cJ° 

*£ 

o* 

r_, 

O 

< 

•£    O 

>^   CD 

r^H       0 

PH 

o 

4^ 

s 

lfe 

"^    "^ 

rVI 

^H 

PH 

PQ 

< 

8 

< 

0 

"o 

o 
o 

0 

13 

^ 

0 

0 

'o 

"3 

0 

'o 

0 

0 

1 

0 

t/Tyj 

W  j 

13 

ffl 

&3 

13 

H^ 

^t 

rS 

So 

X  K 

CO 

HH1 

!>•» 

ffi5 

2 

KI 

^ 

K 

Jj 

ffi" 

^ 

0 
• 

0 

c_T 

>^ 

cT 

PH 

c5" 

>^> 

cf 

g» 

Q 

4-> 

rC 

0 

*5 

H 

J>4 

;_, 

E 

S 

w 

PH 

PQ 

J 

W) 

M 

H 

I 

0 

CD 

0 

1 

0 

CD 

OM 

IH 

CD 
^ 

0^ 

^H* 

CD 

h 
Ed 

^s 

CD 

^ 

4^> 
CD 

^ 

CD 

'"S 

4J 

CD 

'"^ 

"S 

OXIDES,  : 

s 

"CD 

i 

!* 

3 

1 

& 

§ 

4-> 
^ 

PQ 

ffi 

^ 
S 

in 

,  * 

^ 

H 

!>. 

>^ 

J 
O 

HH 

rb 

— 

,d 

KM 

HH 

4^ 

HH 

&' 

S 

< 

K 

0 

1 

0 

d° 

S 

PM 

o" 

PQ 

d5 

< 

60 


PARAFFIN    OR    METHANE    SERIES. 


61 


Methods  of  Forming  the  Compounds  of  the  Methyl  Series. 

—The  starting  point  is  generally  the  alcohols.  The  ethers, 
simple  and  compound,  are  produced  by  the  action  of  acids 
on  the  alcohols.  The  aldehydes  are  produced  by  partial 
oxidation,  the  acids  by  complete  oxidation;  many  of  the 
acids  exist  ready  formed  in  nature. 

The  alcohols  will  be  described  first.  They  are  often 
called  the  monatomic  alcohols,  because  they  contain  a 
monatomic  (i.  e.,  monad)  radicle. 

CONSPECTUS  OF  MONATOMIC  ALCOHOLS. 


FORMULA. 

SYSTEMATIC 
NAME. 

COMMON  NAME. 

SOURCE. 

CH3OH 

Methyl 

Wood  spirit 

Distillation  of  wood. 

C2H5OH 

Ethyl 

Alcohol 

Fermentation. 

C3H7OH 

Propyl 

Propyl  alcohol 

M 

C4H9OH 

Butyl 

Butyl 

M 

C6HUOH 

Pentyl 

Amyl 

11 

Fusel  oil 

C6H13OH 

Hexyl 

Caproic  alcohol 

C7H15OH 

Heptyl 

^Enanthic  " 

Action    of    KHO    on 

castor  oil. 

C8H17OH 

Octyl 

From  parsnip  oil. 

C9H19OH 

Nonyl 

C10H21OH 

C12H25OH 

C14H29OH 

C16H33OH 

Hexadecyl 

Cetyl 

Spermaceti. 

C18H37OH 

CsoHaiOH 

Triakontyl  (my- 

ricyl  alcohol) 

Beeswax. 

Methyl  alcohol,  (CH3)HO,  wood  spirit,  is  usually  made 
by  distilling  wood.  The  crude  material  is  purified  to 
such  an  extent  that  it  has  very  little  odor  and  closely 
resembles  ethyl  alcohol  in  its  physical  properties.  Pure 
methyl  alcohol  is  a  colorless,  inflammable  liquid  of  pleasant 


62  ORGANIC    CHEMISTRY. 

odor  and  soluble  in  water,  ethyl  alcohol,  ether  and 
glycerol.  It  boils  at  66.5°.  The  effects  on  the  animal 
system  are  so  dangerous  as  to  even  prohibit  its  use  in 
small  proportions  in  making  preparations  intended  for  in- 
ternal administration;  the  most  prominent  effect  follow- 
ing its  use  is  blindness,  due  to  atrophy  of  the  optic  nerve. 
Methylated  spirit,  a  mixture  of  90  parts  common  alco- 
hol with  10  parts  of  crude  methyl  alcohol,  was  formerly 
largely  used  in  Great  Britain  as  a  tax-free  substitute  for 
ordinary  alcohol,  the  presence  of  the  methyl  alcohol  render- 
ing it.  unfit  for  use  in  any  preparations  to  be  given  inter- 
nally. 

H  O 

II 
H— D— C— H         H— C— H 

A 

Hydroxymethane  Methyl  aldehyde 

(Methyl  alcohol,  carbinol)  •       (Formaldehyde) 

The  presence  of  methyl  alcohol  in  ethyl  alcohol  may  be  deter- 
mined as  follows:  The  suspected  sample  (which  may  be  first 
fractionally  distilled)  is  diluted  with  water  to  reduce  the  strength 
to  about  10  per  cent.  A  copper  spiral,  made  by  winding  copper 
wire  closely  around  a  lead  pencil  or  similar  cylindrical  body,  for 
a  distance  of  about  5  c.c.,  is  heated  to  redness  and  plunged  into 
the  diluted  alcohol;  this  operation  is  repeated  five  or  six  times, 
after  which  the  liquid  is  gently  boiled  for  a  few  minutes  and  filtered 
if  necessary.  The  effect  of  the  heated  copper  spiral  is  to  reduce 
both  the  ethyl  and  methyl  alcohols  to  the  corresponding  aldehydes. 
The  ethyl  aldehyde  being  more  volatile  is  removed  by  boiling 
after  which  the  remaining  liquid  may  be  tested  for  the  presence 
of  formaldehyde  by  any  of  the  standard  methods.  This  process 
will  detect  as  small  a  quantity  as  2  per  cent,  of  methyl  alcohol  in 
ethyl  alcohol. 


PARAFFIN    OR    METHANE    SERIES.  63 

Ethyl  alcohol,  (C2H5)HO,  common  alcohol,  grain  alcohol, 
spirit  of  wine,  is  produced  in  the  vinous  fermentation  of 
sugar,  carbon  dioxide  being  the  only  other  product  formed 
in  large  amount;  it  can  also  be  prepared  synthetically. 
The  fermented  spirit  is  concentrated  by  distillation  in  a 
rectifying  still  and  column,  but  the  strongest  thus  pre- 
pared contains  about  5  per  cent,  of  water  and  constitutes 
the  ordinary  alcohol  of  commerce.  To  withdraw  all  water 
it  is  necessary  to  distil  with  quicklime,  anhydrous  copper 
sulphate  or  calcium  chloride,  by  which  absolute  alcohol  is 
formed. 

Alcohol  is  a  colorless,  transparent,  inflammable  liquid, 
of  a  faint  but  characteristic  odor  and  a  sharp  burning 
taste,  sp.  gr.  about  0.825,  boiling  point  78°.  It  is  soluble 
in  all  proportions  in  water,  ether  and  glycerol  and  is 
largely  used  as  a  solvent.  Absolute  alcohol  is  a  slightly 
better  solvent  than  ordinary  alcohol  for  some  volatile  oils 
and  resins.  It  attracts  moisture  so  readily  from  the  air 
that  it  is  difficult  to  preserve  it  in  the  absolute  condition. 

Proof -spirit  contains,  by  weight,  50.8  parts  of  absolute 
alcohol  to  49.2  of  water  and  has  a  sp.  gr.  of  0.920.  Alcohol 
is  contained  in  wine,  beer  and  spirits.  Whisky,  brandy 
and  other  spirits  contain  from  40  to  50  per  cent,  of  alcohol; 
wines,  from  17  (port  and  madeira)  to  7  or  8  (hock  and  light 
clarets)  per  cent. ;  porter  and  strong  ale  contain  from  6  to  8 
per  cent.,  lager  beer  about  3.5  per  cent.;  the  mild  fer- 
mented liquors  known  as  mead,  root-beer,  spruce-beer, 
contain  from  i  to  i  per  cent.  The  effervescence  of  fer- 
mented liquids  is  due  to  the  carbon  dioxide  which  is 
produced  with  alcohol: 

Alcohol. 
'  C6H12O6  breaks  up  into  2C2H6O  +  2CO2 


64  ORGANIC    CHEMISTRY. 

The  carbon  dioxide  in  sparkling  alcoholic  beverages,  is 
retained  by  bottling  the  liquid  before  the  fermentation 
is  over. 

In  the  production  of  alcohol  by  fermentation  other 
substances  are  formed,  some  of  which  contaminate  the 
product  even  after  repeated  distillation.  One  of  these, 
known  as  fusel  oil,  consists  of  a  mixture  of  several  of  the 
higher  members  of  the  same  homologous  series.  The 
presence  of  this  impurity  is  usually  determined  by  the 
characteristic  odor  which  is  left  on  filter  paper  after  a  small 
quantity  of  the  alcohol  has  been  allowed  to  evaporate 
from  it.  Aldehyde,  which  is  an  oxidation  product  of 
alcohol;  is  sometimes  present  and  may  be  detected  by  the 
brown  color  which  it  produces  with  a  solution  of  potassium 
hydroxide. 

Experiment  4. — Place  about  5  c.c.  of  absolute  alcohol  in  one 
testtube  and  about  5  c.c.  of  ordinary  alcohol  in  another  testtube. 
Add  about  0.5  gram  of  anhydrous  copper  sulphate  to  each  and 
note  the  difference  in  the  effect. 

Experiment  5. — Dissolve  about  100  grams  of  cane  sugar  in  1000 
c.c.  of  water  and  place  the  solution  in  a  large  bottle  or  wide- 
mouthed  jar.  Add  to  this  solution  about  one-fourth  of  a  cake  of 
compressed  yeast  and  stand  the  mixture  aside  for  fermentation  to 
take  place.  When  the  fermentation  is  complete,  which  may  be 
known  by  no  more  bubbles  of  carbon  dioxide  being  given  off, 
transfer  the  solution  to  a  large  distilling  flask  and  collect  about 
100  c.c.  of  the  first  distillate  which  comes  over.  Test  this  distillate 
for  alcohol  by  means  of  the  iodoform  reaction. 

Sodium  etkylate  is  obtained  by  the  action  of  sodium  upon 
alcohol.  The  substitution  takes  place  rapidly,  hydrogen 
being  evolved,  but  only  the  hydroxyl  group  is  attacked. 
The  resulting  compound  is  a  solid,  very  soluble  in  water 
and  alcohol,  and  corrosive.  It  saponifies  fats  *nore  rap- 
idly than  an  aqueous  solution  of  sodium  hydroxide. 


PARAFFIN    OR    METHANE    SERIES.  65 

H    H 

H— C— C— O— Na 
H    H 

Sodium  ethylate 
(Sodium  ethoxide) 

Amyl  alcohol,  Pentyl  alcohol,  C5HnHO. — Eight  isomers, 
four  primary,  three  secondary  and  one  tertiary  (see  be- 
low) are  possible;  all  have  been  obtained.  Several  have 
asymmetric  carbon.  Some  of  the  amyl  alcohols  are  by- 
products in  vinous  fermentations  and  hence  are  found  in 
alcoholic  beverages.  They  are  especially  noticeable  in  the 
fermented  liquor  from  potato  starch  (hence  the  name 
"amyl"  alcohol,  from  a  Greek  word  for  starch).  These 
alcohols  may  be  separated  in  part  by  distillation.  The 
mixture  of  them  thus  obtained  is  known  commercially  as 
"fusel  oil."  It  is  supposed  to  be  very  poisonous  and  to 
give  very  injurious  properties  to  liquors  containing  even 
small  amounts,  but  these  points  are  not  established.  The 
pure  amyl  alcohols  are  colorless  liquids,  nearly  insoluble 
in  water  and  of  a  hot,  acrid  taste. 

The  higher  alcohols  are  mostly  oily  liquids  or  wax-like 
solids. 

Isomeric  Forms  of  Alcohols. — Methyl  and  ethyl  alcohols 
present  only  one  form,  but  a  number  of  isomers  of  the 
higher  alcohols  have  been  obtained.  Comparison  of  these 
isomers  has  led  to  their  division,  according  to  an  assumed 
arrangement  of  the  carbon  atoms,  into  three  groups, 
primary,  secondary  and  tertiary  alcohols. 
5 


66  ORGANIC    CHEMISTRY. 

Primary  alcohols  contain  the  group  CH2OH  joined  to 
one  alcohol  radicle;  secondary  alcohols  contain  the  group 
CHOH  joined  to  two  radicles;  and  tertiary  alcohol  con- 
tains the  group  COH,  joined  to  three  radicles. 

Illustrations  of  these  principles  are  found  in  the  struc- 
tural formulas  of  the  three  butyl  (tetryl)  alcohols.  The 
secondary  form  contains  asymmetric  carbon  indicated  by 
italic  symbol: 

H    H    H    H  H     H     H 

H-O— C— C— C— C-H  H-O— C—  C— C-H 

H    H    H    H  H— C     H     H 

HAH 

Primary  butyl  alcohol      •  Secondary  butyl  alcohol 

H 

H— C— H 

I  H 

H— O— C— C< 

I      i      H 
H— C     H 

HAH 

Tertiary  butyl  alcohol 

ETHERS. 

The  primary  alcohols,  by  the  action  of  bodies  which  have 
an  affinity  for  water  (sulphuric  and  phosphoric  acids), 
are  converted  into  oxides,  called  ethers.  A  compound 


ETHERS.  67 

ether  or  ester  is  the  replacement  of  the  hydrogen  of  an  acid 
by  one  or  more  molecules  of  a  hydrocarbon.  The  only 
simple  ether  of  any  importance  is: 

Ethyl  oxide,  (C2H5)2O,  ether,  often  wrongly  called  sul- 
phuric ether,  made  by  the  action  of  sulphuric  acid  upon 
alcohol.  Acid  ethylsulphate  is  first  formed  and  then 
decomposed : 

Alcohol.  Acid  ethylsulphate.- 

(C2H5)HO    +   H2S04    ==    (C2H5)HS04   +   H2O 
Another  molecule  of  alcohol  is  then  acted  upon,  thus: 

Ether. 

(C2H5)HO    +    (C2H5)HS04  =   H2S04   +    (C2H5)2O 

It  will  be  seen  from  these  reactions  that  in  theory  the 
sulphuric  acid  is  continuously  re-generated.  This  is  not 
true  in  practice  on  account  of  reactions  between  the  sul- 
phuric acid  and  the  impurities  in  the  alcohol. 

Ether  is  a  colorless  mobile,  very  volatile  liquid,  of 
a  characteristic  odor,  boiling  at  37°.  Sp.  gr.  0.723.  Its 
vapor  is  inflammable  and  very  heavy.  It  is  insoluble 
in  water,  soluble  in  alcohol  and  is  a  solvent  for  fats,  fixed 
and  volatile  oils,  resins  and  many  other  proximate  prin- 
ciples. Its  vapor  is  anesthetic. 

Experiment  6. — Warm  a  beaker  of  about  250  c.c.  capacity 
slightly  in  the  flame  of  a  bunsen  burner;  pour  into  it  a  few  c.c.  of 
ether  and  cover  the  beaker  with  a  watch  glass  for  a  few  moments. 
Take  another  beaker  of  the  same  size  and,  having  removed  the 
watch  glass,  invert  the  beaker  containing  the  ether  vapor  over  the 
empty  beaker,  with  a  motion  similar  to  that  used  in  pouring 
liquids  from  one  vessel  to  another.  Test  the  vapor  in  the  second 
beaker  for  inflammability,  using  a  lighted  taper.  This  shows  that 
the  vapor  of  ether  is  considerably  heavier  than  atmospheric  air. 


68  ORGANIC    CHEMISTRY. 

The  molecular  structure  of  simple  and  mixed  ethers  is 
illustrated  by  the  annexed  formulas: 

H     H  H     H  H     H  H 

H— C— C— O— C— C-H       H-C— C— O— C— H 

H    H  II     H  H     H  H 

Ethyl  ether.  Methylethyl  ether. 

Heavy  oil  of  wine  is  a  by-product  in  the  manufacture  of 
ether  and  consists  of  a  mixture  of  sulphuric  esters  of  the 
hydrocarbons.  When  mixed  with  an  equal  volume  of 
ether  it  constitutes  ethereal  oil  which  is  one  of  the  con- 
stituents of  the  official  compound  spirit  of  ether  (Spiritus 
(Biker is  compositus),  commonly  known  as  Hoffman's  anodyne. 

Esters,  Compound  Ethers. — Many  of  these  have  char- 
acteristic odors  and  are  the  flavoring  materials  of  flowers 
and  fruits.  They  can  be  made  synthetically. 

The  usual  method  of  preparation  is  to  heat  a  mixture  of 
the  sodium  salt  of  the  proper  acid,  the  alcohol  containing 
the  proper  radicle  and  sulphuric  acid.  Thus  to  produce 
ethyl  acetate,  sodium  acetate,  ethyl  alcohol  and  sulphuric 
acid  are  used: 

C2H5HO  +  NaC2H302  +  H2SO4  =  C2H5C2H3O2  +  NaHSO4  +  H2O 

Mixtures  of  esters  are  used  as  imitation  flavors.  The 
following  are  the  more  important: 

Methyl  acetate,  CH3C2H3O2,  is  a  colorless  liquid  used  as  a 
solvent.  In  association  with  acetone,  it  dissolves  pyr- 
oxylin. 

Methyl  salicylate  C6H4OHCOOCH3  constitutes  the 
greater  portion  of  oil  of  wintergreen  and  oil  of  birch. 


ETHERS.  69 

Ethyl  acetate,  C2H5C2H3O2,  is  a  colorless  liquid  of  a 
characteristic  agreeable  fruity  odor.  It  is  largely  used  in 
compounding  fruit  essences. 

Ethyl  butyrate,  C2H5C4H7O2,  is  also  largely  used  in 
artificial  flavoring  extracts. 

Ethyl  bromide,  C2H5Br,  is  an  anesthetic. 

Ethyl  nitrite,  C2H5NO2,  is  the  active  ingredient  of  the 
official  spirit  of  nitrous  ether,  commonly  known  as  sweet 
spirit  of  nitre.  (Spiritus  cetheris  nitrosi.) 

Amyl  nitrite,  C5H11NO2,  is  made  by  the  action  of  nitric 
acid  upon  amyl  alcohol.  It  is  a  yellowish  liquid,  of  well- 
marked  odor,  boiling  at  96°.  It  is  used  in  medicine  by 
inhalation,  for  the  relief  of  angina  pectoris. 

Amyl  acetate,  C5HnC2H3O2,  is  another  of  the  esters 
largely  used  in  compounding  artificial  fruit  flavors.  It  is 
also  used  as  a  solvent,  especially  in  preparing  the  lac- 
quering solutions  and  the  so-called  pyroxylin  varnishes. 

Experiment  7. — In  a  tubulated  retort  place  5  grams  of  red 
phosphorus  and  25  c.c.  of  absolute  alcohol.  Connect  the  retort 
with  a  well-cooled  condenser,  and  insert  a*  separatory  funnel  pro- 
vided with  a  glass  stop-cock  through  the  tubulure  of  the  retort, 
making  a  tight  joint  by  means  of  a  rubber  stopper.  Place  25 
grams  of  bromine  in  the  separatory  funnel,  and,  having  ascertained 
that  all  the  connections  are  perfect,  allow  the  bromine  to  flow  into 
the  mixture  of  red  phosphorus  and  alcohol  drop  by  drop.  After 
allowing  the  flask  to  stand  for  several  hours,  apply  a  gentle  heat 
to  the  flask  and  collect  the  ethyl  bromide  (bromethane)  which 
distils  over.  Wash  the  distillate  with  water  in  a  separatory 
funnel ;  dry  it  by  adding  calcium  chloride  and  allowing  it  to  stand ; 
then  redistil  and  make  notes  of  the  boiling  point,  odor  and  specific 
gravity. 

Experiment  8. — Mix  equal  quantities  of  alcohol  and  acetic  acid 
in  a  testtube,  cautiously  add  a  little  concentrated  sulphuric  acid 
and  warm  the  mixture  gently.  The  fragrant  odor  of  ethyl  acetate 


70  ORGANIC    CHEMISTRY. 

will  be  observed.  This  reaction  may  be  used  as  a  test  for  the 
presence  of  either  acetic  acid  or  alcohol. 

Experiment  9. — Dissolve  about  one  gram  of  sodium  nitrite  in 
2  c.c.  of  water  in  a  testtube.  Add  about  i  c.c.  of  alcohol  and 
then  cautiously  pour  in  a  mixture,  previously  made,  of  i  c.c.  of 
sulphuric  acid  and  2  c.c.  of  water.  The  vapor  of  ethyl  nitrite 
(C2H5NO2)  is  evolved,  which  may  be  recognised  by  the  fragrant 
ethereal  odor  resembling  apples. 

Experiment  10. — Cautiously  mix  equal  volumes,  5  c.c.,  of  con- 
centrated sulphuric  acid  and  alcohol  and  dilute  the  mixture  with 
about  ten  times  its  bulk  of  water.  Add  barium  carbonate  in 
small  portions  until  effervescence  ceases  and  the  liquid  is  neutral. 
Filter  and  examine  the  clear  nitrate  for  barium.  This  is  a  soluble 
compound  of  barium  with  sulphuric  acid,  called  barium  ethyl- 
sulphate,  Ba(C2H5SO4)2. 

Sulphur  Alcohols,  Mercaptans. — The  oxygen  of  organic 
bodies,  as  of  inorganic  bodies,  may  be  replaced  by 
any  other  element  of  the  oxygen  group.  Ethyl  alcohol, 
for  instance,  has  a  corresponding  sulphur  compound, 
C2H5HS,  called  mercaptan.  This  is  a  condensation  of  a 
Latin  phrase  meaning  "to  take  mercury"  on  account  of 
its  action  on  that  element.  The  proper  name  is  ethyl 
hydrosulphide.  The  mercaptans  when  oxidised  form  sul- 
phonic  acids  which  will  be  taken  up  later.  Corresponding 
ethers  also  are  known;  thus  (C2H5)2S,  ethyl  sulphide. 
These  derivatives  are  mostly  strong-smelling  and  irritating 
compounds.  A  few  of  them  exist  ready -formed  in  the 
secretions  of  animals  and  plants.  The  essential  oils  of 
mustard,  garlic  and  horseradish  are  examples,  and  are 
noticed  elsewhere. 

When  the  oxygen  of  carboxyl  is  replaced  by  sulphur 
the  prefix  "thio"  is  generally  employed.  The  following 
structural  formula  shows  one  of  the  positions  of  the  sulphur 
atom.  These  bodies  are,  as  exemplified  by  those  just 
mentioned,  mostly  of  strong,  disagreeable  odor. 


ETHERS.  71 


H-L 


H    O 

II 

C— S— H 


H 

Thiacetic  acid 

When  both  atoms  of  oxygen  are  replaced  the  prefix 
"dithio"  is  used. 

Aldehydes. — These  compounds  are  formed  by  the  re- 
moval of  two  atoms  of  hydrogen  from  the  corresponding 
alcohols,  and  stand  intermediate  between  the  alcohols  and 
the  acids. 

Ethyl  aldehyde,  ethanal,  usually  called  acetic  aldehyde,  or 
simply  aldehyde,  C2H4O,is  often  present  in  liquors,  especially 
in  raw  forms  of  commercial  spirits,  and  probably  gives  to 
such  articles  some  injurious  qualities.  It  is  a  colorless, 
volatile  liquid,  lighter  than  water,  and  boiling  at  21°, 
having  a  powerful  affinity  for  oxygen,  and  therefore  a 
reducing  action.  It  presents  several  isomeric  modifica- 
tions, one  of  which,  par  aldehyde,  a  polymeric  form,  to 
which  the  formula  C6H12O3  has  been  assigned,  has 
hypnotic  properties.  All  the  aldehydes  of  the  series  form 
complicated  compounds,  as  yet  of  little  practical  value. 

The  structural  formula  of  common  aldehyde  is: 

H    O 

I     H 
H— C— C— H 

H 

It  will  be  noted  that  no  hydroxyl  is  present,  and  hence 
aldehyde  has  neither  acid  nor  basic  properties. 

Chloral. — The  substitution  of  three  atoms  of  hydrogen 


72  ORGANIC    CHEMISTRY. 

in  aldehyde,  by  chlorine,  produces  a  colorless  liquid 
heavier  than  water  (sp.  gr.  1.18),  and  boiling  at  94°. 
This  is  trichloraldehyde,  C2HC13O,  chloral.  It  combines 
with  one  molecule  of  water  to  form  a  crystalline,  pungently- 
smelling  solid,  soluble  in  water,  which  is  now  used  under 
the  name  of  chloral  hydrate.  In  alkaline  solution  chloral 
is  decomposed  as  shown  in  the  following  equation: 

Sodium  Sodium 

Chloral.  Hydroxide.         Formate.          Chloroform. 

C2HC13O    +   NaHO    =   NaCHO2   +   CHC13 

The  so-called  chloral  hydrate  (chloral)  is  trichlorethene 
glycol,  C2HC13(HO)2.  It  is  a  hypnotic  and  sedative. 
It  is  often  used  for  drugging  liquor  to  assist  in  the  commis- 
sion of  robbery  or  rape.  It  is  decomposed  by  alkalies 
in  the  same  manner  as  chloral. 

H    Cl  H    Cl 

I       I  H-0      |       | 

O-C— C— Cl  >C— C— Cl 

H— O 

Cl 

Trichloraldehyde  (chloral)  (So-called)  Chloral  hydrate 

If  a  few  grams  of  chloral  hydrate  in  a  narrow  testtube  be  covered 
by  strong  sulphuric  acid,  the  mixture  will  soon  form  in  two  layers; 
the  upper  one  is  chloral,  formed  by  dehydrolysis. 

Experiment  n. — Dissolve  about  i  gram  of  potassium  dichro- 
mate  in  about  10  c.c.  of  water  and  add  an  equal  volume  of  alcohol. 
Cautiously  add  about  3  c.c.  of  concentrated  sulphuric  acid,  note 
the  change  in  the  appearance  of  the  liquid  and  observe  the  odor 
given  off.  The  odor  is  that  of  aldehyde  and  the  green  color  of 
the  liquid  indicates  that  the  potassium  dichromate  has  been 
reduced  to  chromic  sulphate. 

Experiment  12. — Prepare  formaldehyde  from  methyl  alcohol, 
by  the  process  given  on  page  62,  tinder  the  test  for  methyl  alcohol 
in  ethyl  alcohol. 


ETHERS.  73 

Experiment  13. — Dissolve  o.i  gram  of  silver  nitrate  in  distilled 
water;  add  solution  of  sodium  hydroxide,  drop  by  drop,  until  no 
more  precipitate  forms,  and  then  add  ammonium  hydroxide  until 
the  solution  becomes  clear.  Clean  a  testtube  thoroughly  by  wash- 
ing it  with  soap,  by  the  aid  of  the  testtube  brush  or  swab,  and 
rinsing  well  with  water.  Pour  in  the  prepared  silver  solution,  add 
a  few  drops  of  aldehyde  (or  paraldehyde)  and  immerse  the  tube 
in  boiling  water.  Silver  will  be  set  free  by  the  reducing  action  of 
the  aldehyde.  If  the  tube  is  clean,  a  mirror  will  be  formed  on  the 
glass,  but  otherwise  the  precipitate  will  be  loose  and  black. 

Formaldehyde,  CH2O,  has  much  practical  as  well  as 
theoretic  interest.  It  is  produced  by  the  action  of  heated 
copper  oxide  upon  the  vapor  of  methyl  alcohol.  It  is  a 
powerful  antiseptic,  preserving  thoroughly  many  perish- 
able articles.  The  use  of  formaldehyde  in  preserving  ar- 
ticles of  food  and  drink  is  forbidden  by  law,  as  it  forms 
insoluble  compounds  with  many  proteid  substances,  and 
therefore  affects  the  digestibility  of  the  substances  thus 
preserved.  It  is  also  a  powerful  reducing  agent.  Formal- 
dehyde is  considered  by  plant  physiologists  as  the  starting- 
point  in  the  formation  of  the  so-called  "carbohydrates"  of 
the  vegetable  kingdom.  Its  formula  multiplied  by  five 
gives  C5H10O5,  pentose,  forms  of  which  are  common  in 
plants,  and  by  easy  changes  may  produce  the  sugars  and 
starches.  The  commercial  formaldehyde  (formalin)  con- 
sists of  a  40  per  cent,  solution  of  the  gas  in  water. 
This  solution  readily  polymerises  with  the  formation 
of  paraformaldehyde,  C3H6O3,  which  upon  strongly  heat- 
ing again  decomposes  into  formaldehyde,  CH2O. 

Ketones. — By  the  destructive  distillation  of  calcium 
acetate,  a  body  called  acetone,  C3H6O,  is  formed,  differing 
from  aldehyde,  C2H4O,  by  CH2. 

(CH3COO)2Ca    =  CH3COCH3   +   CaCO 


74  ORGANIC    CHEMISTRY. 

Acetone  is  the  type  of  a  group  termed  ketones.  They  con- 
tain carbonyl,  CO,  united  to  two  monad  radicles.  They 
are  reducing  agents,  form  "  osazones  "  (see  page  100)  and 
form  compounds  with  sulphites. 

H    O    H 

I      II      I 
H— C— C— C— H 

A    A 

Acetone 
(Dimethyl  ketone) 

Acetone  is  produced  in  the  destructive  distillation 
of  wood  and  is  used  as  a  solvent  in  many  technical 
processes.  It  is  a  colorless,  transparent  liquid,  of  a 
characteristic,  ethereal  odor,  soluble  in  all  proportions 
in  water,  alcohol  and  ether  and  resembling  the  latter 
liquid  in  its  solvent  effect  on  fats,  oils  and  waxes.  It  is 
also  used  as  a  solvent  for  pyroxylin. 

Experiment  14. — Prepare  a  saturated  solution  of  sodium  acid 
sulphite  in  water,  and  shake  this  with  an  equal  volume  of  acetone. 
A  sulphite  compound  will  be  formed  and  precipitate  in  the  strong 
solution,  but  will  be  dissolved  on  addition  of  water. 


FATTY-ACIDS. 

This  term,  applicable  strictly  to  only  a  few  of  the  series, 
is  applied  to  the  homologous  bodies  derived  from  the 
alcohols  by  substitution  of  two  atoms  of  hydrogen  by  one 
atom  of  oxygen.  It  is  an  extensive  and  important  class; 
nearly  all  are  natural  products.  The  fixed  oils  and  fats 
yield  some  of  the  higher  members  of  the  series.  Some  have 


FATTY-ACIDS.  75 

been  produced  synthetically  by  a  reaction,  of  which  the 
following  is  a  type: 

Ethyl  alcohol.  Acetic  acid. 

C2H60    +   02    =  C2H402    +   H20 

Each  of  the  acids  so  produced  contains  one  carboxyl 
group,  COOH,  the  hydrogen  of  which  can  be  replaced  by  a 
positive  element  or  radicle,  and  this  fact  may  be  shown 
by  writing  each  formula  with  the  carboxyl  distinguished. 
The  lower  members  of  the  series  are  freely  soluble  in, 
and  miscible  with  water,  strongly  acid  and  irritating,  but 
as  the  quantity  of  carbon  and  hydrogen  increases,  the 
compounds  become  more  and  more  oily,  and  the  higher 
members  are  fatty,  feebly  acid,  insoluble  in  water,  but 
soluble  in  alcohol  and  ether. 

Formic  Acid,  HCOOH,  was  originally  obtained  by 
distilling  the  liquid  in  which  the  bodies  of  a  species  of  ant 
(Lat.,  formica)  had  been  macerated.  It  can  be  prepared 
in  quantity  by  heating  oxalic  acid  with  glycerol.  Glycerol- 
formic  ester  is  produced  and  then  decomposed.  The 
equation  shows  that  hydrolysis  and  dehydrolysis  occur. 

C3H5(HO)3  +   (COOH)2   =  C3H5(HO)2CH02   +  CO2  +  H2O 
C3H5(HO)2CHO2    +   H2O    =   HCOOH    +   C3H5(HO)3 

The  glycerol  being  reproduced,  a  small  amount  will  suffice 
for  the  conversion  of  much  oxalic  acid.  Formic  acid  is 
supposed  to  exist  in  the  secretions  of  some  stinging  animals 
and  plants. 

Experiment  15. — Place  about  10  c.c.  of  glycerol  in  a  testtube 
with  about  3  grams  of  oxalic  acid  and  apply  heat  gradually,  by 
means  of  a  bunsen  burner,  taking  care  not  to  raise  the  temperature 
much  above  the  boiling  point  of  water.  Test  the  vapors  occa- 
sionally with  moistened  blue  litmus  paper  and  when  acid  vapors 
are  evolved,  cautiously  note  the  pungent,  irritating  odor  which 
is  due  to  formic  acid. 


76  ORGANIC    CHEMISTRY. 

Although  formic  acid  has  a  higher  percentage  of  oxygen 
than  any  other  member  of  its  series,  it  has  the  greatest 
reducing  power.  This  is  mainly  because  it  contains  an 
aldehydic  structure,  the  group  HCO,  which  is  not  the 
case  with  the  other  normal  fatty-acids.  The  structural 
formula  in  comparison  with  that  of  acetic  acid  shows  this 
point : 

O  HO 

II  I      II 

H— C— O— H  H— C— C— O— H 

H 

Formic  acid  Acetic  acid 

Formic  acid  is  a  colorless,  highly  irritating  liquid. 

Acetic  Acid,  CH3COOH. — This  occurs  in  small  quan- 
tities in  animal  and  plant  juices.  In  the  dilute  form  it 
constitutes  vinegar,  which  contains  from  3  to  6  per  cent, 
of  the  acid,  and  is  usually  made  by  oxidising  very  weak 
alcohol  in  the  presence  of  a  ferment.  Acetic  acid  is  also 
produced  in  the  distillation  of  wood.  The  first  distillate  is, 
in  this  case,  generally  contaminated  with  tar  and  phenol- 
compounds  and  is  called  pyroligneous  acid.  It  is  used 
commercially  in  preserving  meats,  and  is  often  sold  under 
the  name  "Liquid  Smoke."  Pure  acetic  acid  is  a  color- 
less, corrosive  liquid,  solidifying  at  17°  (hence  often  called 
"glacial  acetic  acid"),  and  boiling  at  119°.  The  dilute 
forms  are  less  active,  and  in  vinegar  its  effects  are  quite  mild. 

ACETATES. — The  most  important  of  these  are: 

Potassium  acetate,  KC2H3O2,  a  deliquescent  salt,  much 
used  in  medicine  as  a  diuretic. 

Sodium  acetate,  NaC2H3O2,  which  forms  efflorescent 
crystals,  containing  3H2O. 

Ammonium  acetate,   (NH4)C2H3O2,  is  used  in  medicine 


FATTY-ACIDS.  77 

in  the  form  of  a  freshly  prepared  solution  in  water,  called 
spirit  of  Mindererus.     (Liquor  ammonii  acetatis.) 

Lead  acetate,  Pb(C2H3O2)2,  sugar  of  lead,  made  by  dissolv- 
ing lead  monoxide  in  acetic  acid,  forms  white  crystals, 
soluble  in  water.  By  boiling  this  solution  with  lead 
monoxide,  a  considerable  amount  of  the  latter  is  dissolved, 
and  the  subacetate,  more  correctly  oxyacetate,  is  formed, 
called  Goulard's  extract,  in  concentrated  solution  (Liquor 
plumbi  subacetatis)  ,  and  when  much  diluted,  Lead  water 
(Liquor  plumbi  subacetatis  dilutus). 

Copper  acetate,  Cu(C2H3O2)2,  is  not  important;  but  an 
irregular  and  variable  compound  of  it  with  copper  hydrox- 
ide, known  as  verdigris,  is  made  by  exposing  alternate  • 
layers  of  sheet  copper  and  refuse  grape  skins  to  the  air; 
ethyl  alcohol  is  formed  and  then  converted  into  acetic 
acid  which  acts  on  the  copper. 

Zinc  acetate,  Zn(C2H302)2+2H2O,  is  a  white  efflorescent 
salt  which  is  used  as  an  astringent. 

A  derivative  of  acetic  acid,  acetoacetic  acid,  the 
structural  formula  of  which  is  given,  is  of  some  theoretic 
interest.  Its  ethyl  ester,  obtained  by  the  action  of  sodium 
upon  ethyl  acetate,  the  hydrogen  of  the  carboxyl  being 
replaced  by  ethyl  has,  contrary  to  what  theory  indicates, 
acid  qualities  and  takes  up  sodium  in  exchange  for  a  hy- 
drogen atom  that  is  in  union  with  carbon.  The  reason  for 
this  unusual  action  has  not  been  ascertained,  but  there  is 
probably  tautomerism  in  the  formula. 

H     O    H     O 

I      II      I      II 
H—  C—  C—  C—  C—  O—  H 


Acetoacetic  acid 


ORGANIC    CHEMISTRY. 


Acetic  anhydride,  (C2H3O)2O,  used  in  some  analytic 
and  research  operations,  is  obtained  by  distilling  anhy- 
drous sodium  acetate  with  phosphoric  oxychloride.  Struc- 
turally, it  resembles  the  ethers,  but  acid  radicles,  not 
hydrocarbons,  are  united  by  oxygen. 

HO  OH 

I      II  II      I 

H— C— C— O— C— C— H 


H 


H 


Acetic  anhydride 


HOMOLOGOUS  SERIES  OF  FATTY-ACIDS. 


Common 
Name. 

Empirical 
Formula. 

Properties. 

Natural  Source. 

Formic  

CH2O2 

Colorless  volatile  liquid. 

In  red  ants  and  some  other 

insects  and  in  some  sting- 

ing plants. 

Acetic    ...    . 

C2H4O2 

Colorless  pungent  liquid. 

Oxidation    of    alcohol    and 

sugar. 

Propionic  .  .  . 

C3Hf)02 

Crystalline  solid. 

Butyric  

C4H802 

Colorless  liquid  of  disagree- 

Butter   and     other    animal 

able  odor. 

secretions. 

Valeric  

C5H1002 

Colorless  liquid  of  disagree- 

Valerian root. 

able  odor. 

Caproic   .... 
Enanthylic  .  . 

CoHi"O2 
C7H1402 

Colorless  oily  body. 
Slightly  soluble   in   water; 

Butter  and  coconut  oil. 
Oxidation  of  castor  oil. 

has  an  agreeable  odor. 

Butter,  coconut  and  castor 

Caprylic  .... 

C8H16O2 

oils. 

Pelargonic  .  . 
Capric   

Crystalline  solid. 
Crystalline  mass  having  the 

Geranium  leaves. 
Butter  and  coconut  oil. 

odor  of  sweat. 

Laurie  
Myristic  .... 

Cuuf8ol 

Silky  crystals. 
Crystalline  scales. 

In  coconut  oil. 
In  nutmeg  and  coconut  oil. 

Palmitic  

Fat-like  solid. 

Most  natural  fats. 

Margaric  .  .  . 

CnH3402 

it            11 

Stearic  

C18H36O.> 

Arachidic.  .  . 

C20H40O2 

White  crystalline  fatty  solid. 

Peanut  oil. 

Behenic  .... 

C22H4402 

«i              <t             ii        K 

Oil  of  ben. 

Hyenic  

'Resembles  cerotic. 

Cerotic  
Mellissic.  .  .  . 

C27H5402 
C3oHcoO2 

Crystallises  in  small  grains. 

Free  in  beeswax. 
Derived  from  beeswax. 

Butyric    (Tetrylic)    Acid,    C3H7,COOH.— This    may    be 
obtained  from  butter-fat,  from  some  fruit  flavors,  and  by 


FATTY-ACIDS.  79 

fermentation  of  sugar  with  cheese  and  chalk.  It  is  a 
colorless  liquid  having  the  disagreeable  odor  of  rancid 
butter.  Ethyl  butyrate  is  produced  by  heating  butter- 
fat  with  alcoholic  solution  of  sodium  hydroxide.  The 
reaction  is  not  known. 

Valeric  (Pentylic)  Acid,  C4H9COOH,  is  found  in 
valerian  root  and  in  other  plants.  Four  isomeric  modifi- 
cations are  possible.  The  ordinary  form  is  a  colorless 
liquid  of  a  disagreeable  odor.  Several  valerates,  often 
called  valerianates,  are  used  in  medicine;  among  these  are 
those  of  zinc  and  ammonium. 

Stearic  Acid,  HC18H35O2,  can  be  obtained  from  most 
of  the  solid  animal  fats,  and  from  some  vegetable  fats.  It 
is  a  white,  crystalline  body  which  can  be  distilled.  It  is 
insoluble  in  water,  slightly  soluble  in  alcohol.  The  white 
candles  called  stearin  are  generally  made  of  stearic  acid. 
Its  only  use  in  medicine  is  with  sodium  carbonate,  with 
which  it  forms  a  soap,  a  vehicle  for  the  administration  of 
glycerol  in  suppositories. 

Salts  of  Fatty-Acids  Soaps. — By  substituting  the  single 
atom  of  replaceable  hydrogen  of  the  fatty-acids  a  series 
of  bodies  is  obtained  all  of  which  might  be  called  "soaps," 
but  it  is  only  with  the  higher  members  of  the  series 
that  the  peculiar  physical  and  chemical  characters  of 
the  soaps  are  noticeable.  The  derivatives  of  the  lower 
members  are  generally  soluble  in  water,  but  in  the  higher 
members  most  of  the  compounds  are  insoluble,  except 
those  formed  by  potassium,  sodium  and  ammonium. 
Lead,  calcium  and  zinc,  for  instance,  form  insoluble  soaps. 

The  soluble  soaps  are  those  which  are  valuable  for  their 
detergent  properties.  When  sodium  hydroxide  is  used 
in  combination  with  olive  oil,  a  "castile"  soap  is  produced 
which  is  a  hard  soap.  Potassium  hydroxide  produces 


8o  ORGANIC    CHEMISTRY. 

the  so-called  soft-soaps;  the  official  soft  or  green  soap  (Sapo 
mollis),  being  made  from  potassium  hydroxide  and  linseed 
oil.  Among  the  insoluble  soaps  which  are  of  common 
occurrence  may  be  mentioned :  Lead  plaster  which  is  lead 
oleo-stearate,  made  by  saponifying  olive  oil  with  lead 
oxide,  glycerol  being  obtained  as  a  by-product.  The  so- 
called  Carron  oil,  made  by  adding  lime  water  (solution  of 
calcium  hydroxide)  to  linseed  oil  is  an  insoluble  calcium 
soap  formed  with  the  fatty-acids  of  linseed  oil. 


SUBSTITUTION  DERIVATIVES  OF  THE  FATTY-ACIDS. 

The  hydrogen  that  is  part  of  the  radicle  of  these  acids 
may  be  substituted  by  members  of  the  chlorine  group, 
particularly  by  chlorine  itself.  From  acetic  acid  we  get 
three  compounds,  which  resemble  the  original  acid: 

HC2H3O2 Acetic  acid. 

HC2H2C1O2 Monochloracetic  acid. 

HC2HC12O2 Dichloracetic  acid. 

HC2C13O2 Trichloracetic  acid. 

These  compounds  are  usually  obtained  by  the  direct 
action  of  chlorine.  By  indirect  means,  the  use  of  phos- 
phoric chloride,  PC15,  for  instance,  the  chlorine  may  be 
made  to  replace  the  hydroxyl  of  the  acid ;  in  this  manner 
the  acid  properties  are  removed,  and  chlorides  formed  with 
the  acid  radicles.  Acetic  acid  gives  the  following: 

Acetic  acid.  Acetyl  chloride. 

CH3COOH    +   PC15    =  CH3COC1   +    POC13   +   HC1 
Similar  compounds  may  be  obtained  with  bromine. 


OLEFINS  OR  METHENE  SERIES.  8l 

OLEFINS  OR  METHENE  SERIES. 

M  ethene,  the  first  member  of  the  series,  has  not  yet  been 
obtained.  Ethene,  C2H4,  ethylene,  the  second  member  of 
this  series,  was  called,  when  first  discovered,  olefiant  (oil- 
making)  gas,  because  it  combines  with  chlorine  to  form  an 
oily  liquid;  for  this  reason  the  series  has  been  called  the 
olefins.  They  are  dyad  radicles,  which  form  alcohols, 
ethers  and  other  derivatives;  but  these  derivatives  are 
greater  in  number  than  from  monad  radicles,  on  account 
of  the  higher  valency.  Two  series  of  acids  are  yielded 
by  the  action  of  oxygen  on  the  alcohol,  instead  of  one, 
as  in  the  case  of  the  monad  radicles. 

The  ratio  between  the  weights  of  the  hydrogen  and 
carbon  is  the  same  in  all  members  of  the  series,  hence 
the  percentage  composition  is  the  same,  but  the  mo- 
lecular weight  increases.  The  members  of  the  series  are 
polymeric  isomers. 

DERIVATIVES  OF  OLEFINS. — The  olefins  combine  di- 
rectly with  the  halogens.  Ethene  dichloride  C2H4C12, 
was  originally  called  Dutch  liquid,  because  discovered  by  an 
association  of  Dutch  chemists. 

By  indirect  means,  oxides  esters  and  hydroxides  may  be 
formed.  The  hydroxides  contain  two  molecules  of  HO 
and  are  known  as  DIATOMIC  ALCOHOLS  or  GLYCOLS. 
Each  of  these  alcohols  yields  by  oxidation  two  acids, 
one  derived  by  the  replacement  of  two  atoms  of  hydrogen 
by  one  atom  of  oxygen,  and  the  other  by  the  replacement 
of  four  atoms  of  hydrogen  by  two  atoms  of  oxygen.  The 
first  is  the  lactic  acid  series;  the  second,  the  oxalic  acid 
series.  For  instance,  ethene  glycol  gives  the  following: 
6 


82 


ORGANIC    CHEMISTRY. 


C2H4(HO)2 
C2H4(HO)2 


O4 


H2O 


Glycolic  acid. 

HOCH2COOH 

Oxalic  acid. 

COOHCOOH 


Oxalic  acid  is,  therefore,  dicarboxyl.  Methene  glycol, 
CH2(HO)2,  has  not  been  obtained.  By  oxidation  it  could 
form  but  one  acid,  carbonic,  (HO)2CO,  which  may  be 
regarded  as  the  first  member  of  the  first  series. 


Radicle. 

Oxides, 
Ethers. 

Hydroxides, 
Alcohols. 

Acids  by  first 
oxidation. 

Acids  by  second 
oxidation. 

Glycolic  acid. 

Oxalic  acid. 

C2H4 

C2H40 

C2H4(HO)2 

C2H403 

C2H204 

Lactic  acid. 

Malonic  acid. 

C3H6 

C3H60 

C3H6(HO)2 

C3H6O3 

C3H404 

Oxybutvric  acid. 

Succinic  acid. 

C,H8 

C4H80 

C4H8(HO)2 

C4H803 

C4H604 

The  acids  of  the  first  series,  containing  one  molecule 
of  alcoholic  hydroxyl  and  one  molecule  of  carboxyl,  are 
called  hydroxy-acids. 

Ethene  oxide,  C2H4O,  is  isomeric  (more  accurately, 
metameric),  with  common  aldehyde.  It  is  a  three- 
membered  closed  chain,  the  oxygen  atom  being  one  mem- 
ber of  the  chain  (see  under  "  Heterocyclic  "  compounds). 

The  structural  relations  of  ethene  (ethylene)  glycol  and 
its  two  acid  derivatives,  together  with  two  important  salts 
of  oxalic  acid  are  shown  in  the  annexed  formulas: 


H    H 

H 


H    H 

U 


H— C— C— H      O=C— C— H 


H    H 

Ethene  glycol 
(Dihydroxyethane) 


H 

Glycolic  acid. 


OLEFINS    OR    METHENE    SERIES. 


H    H 

i 


Na   H 


O 


Ca 

oAo 


O    O 
O=C— C=O      O=C— C=O      O:=C— C=O 


Oxalic  acid 
(Dicarboxyl) 


Acid  sodium  oxalate 


Calcium  oxalate 


Acid  Derivatives  of  the  Glycols. — These  are  the  most 
important.  The  first  (lactic)  series  is  monobasic,  that 
is,  has  a  single  atom  of  replaceable  hydrogen;  the  second 
(oxalic  series)  is  dibasic,  that  is,  has  two  atoms  of  re- 
placeable hydrogen. 

LACTIC  SERIES. 


Name. 

Formula. 

Source. 

Gly  colic  . 

CoH.Oo 

By  oxidation  of  ethene  glycol 

Lactic          .         ... 

C,HfiOo 

By  fermentation  of  milk  sugar 

Oxybutyric    

C.HoOo 

By  oxidation  of  butyric  acid 

Oxyvaleric  

C,H,nO, 

By  oxidation  of  valeric  acid. 

Leucic 

CH'O 

Occurs  in   animal  products  '     also 

formed     by     decomposition     of 
horn  and  glue. 

Gly  colic  acid  is  found  in  unripe  grapes.  It  is  of  no 
commercial  importance. 

Lactic  Acid,  (HO)C2H4(COOH).— This  important  acid 
exists  in  four  modifications. 

Ordinary  lactic  acid  is  a  product  of  fermentation  of 
milk  sugar  and  is  therefore  found  in  sour  milk  and 
koumyss.  It  is  a  colorless,  syrupy,  very  sour  liquid,  which 
has  not  yet  been  obtained  in  the  solid  state.  It  can  be 
obtained  in  quantity  by  allowing  a  mixture  of  cane  sugar, 
cheese,  sour  milk  and  chalk,  or  zinc  oxide  to  ferment  for 


84  ORGANIC    CHEMISTRY. 

several  days.  The  resulting  calcium  or  zinc  lactate  can  be 
purified  and  lactic  acid  obtained  from  it.  It  is  optically 
inactive,  but  consists  of  equal  parts  of  dextro-  and  levoro- 
tatory  forms,  which  can  be  separated  by  several  methods. 
Such  separation  of  isomers  is  termed  "mesotomy"  (Gr. 
cutting  midway).  Dextrolactic  acid  occurs  in  the  juice 
of  flesh  and  is  sometimes  called  sarkolactic  acid. 

Ethene-lactic  acid  is  obtained  synthetically  by  several 
methods.  It  is  optically  inactive.  The  following  formu- 
las show  the  stereochemistry  of  these  compounds.  Asym- 
metric carbon  is  present  only  in  one  arrangement. 

H 

H     O    O  H    H    O 

I       I      II  .11      N 

H-C— C— C— O-H      H-O— C— C— C— O-H 

H     H  H    H 

Active  lactic  acid  Ethene-lactic  acid 

Paralactic  and  ordinary  lactic  acid  (Ethylene  lactic  acid) 

(Ethylidene  lactic  acid) 

d    +   1    =  lactic  acid  of  fermentation 

Several  lactates  are  used  in  medicine  particularly 
ferrous  lactate  and  strontium  lactate.  Lactic  acid  is  one 
of  the  products  of  the  growth  of  fungi  around  the  teeth, 
and  is  an  important  factor  in  dental  caries.  When  lactic 
acid  is  heated  in  dry  air,  several  anhydrides  are  formed 
as  follows: 

2C3H6O3    -  -  H2O    =   C6H10O5,  lactic  anhydride 
C6H1005        -  H20    =   C6H804,    lactide 

Lactide  is  a  stable  compound. 


OLEFINS    OR    METHENE    SERIES.  85 

Experiment  16. — To  5  c.c.  of  a  dilute  aqueous  solution  of  phenol 
add  ferric  chloride  to  obtain  the  characteristic  violet  reaction. 
Add  to  this  solution  a  single  drop  of  lactic  acid  and  observe  that 
the  color  of  the  solution  changes  from  violet  to  a  bright  canary- 
yellow.  This  is  Uffelmann's  reaction  for  detecting  lactic  acid  in 
gastric  juice. 

OXALIC  SERIES. 


Name. 

Formula. 

Source. 

Oxalic 

HoCoO. 

Oxidation    of   sugar     starch     and 

Malonic    
Succinic    

C3H404 
C4H6O4 

cellulose. 
Oxidation  of  malic  acid. 
Distillation  of  amber;   oxidation  of 

Pyrotartaric    .... 
Adipic     
Pimelic 

C5H804 
CeH10O4 
C7H19O, 

fatty-acids. 
Action  of  heat  on  tartaric  acid, 
nitric  on  sebacic  acid. 
'    potassium  hydroxide  on 

Suberic  

0«H  i  /<O  A 

camphoric  acid. 
Action   of  nitric   acid  on  cork  or 

Anchoic 

castor  oil. 
Action  of   nitric    acid   on  coconut 

Sebacic  

oil. 
Distillation  of  oleic  acid 

Rocellic    

C17H,,O. 

Exists  in  some  lichens. 

Oxalic  Acid,  (COOH)2.— The  free  acid  and  its  salts, 
especially  acid  potassium  oxalate  and  calcium  oxalate 
occur  in  many  plants,  generally  in  the  form  of  crystals- 
called  raphides — deposited  in  special  cells.  It  is  now 
made  by  fusing  cellulose,  in  the  form  of  sawdust,  with 
potassium  hydroxide.  It  is  decomposed  by  strong  heat  or 
the  action  of  dehydrating  agents  with  the  production  of 
CO2,  CO  and  H2O.  When  it  is  heated  with  glycerol, 
formic  acid  is  produced. 

Oxalic  acid  forms  colorless  crystals,  having  the  com- 
position H2C2O4,2H2O.  It  is  freely  soluble  in  water,  and  is 
one  of  the  most  rapidly  fatal  poisons  known.  Death  has 
occurred  in  ten  minutes  after  administration.  Soluble 


86  ORGANIC    CHEMISTRY. 

oxalates  are  also  poisonous,  hence  the  antidote  must  be 
some  material  that  will  produce  an  insoluble  compound. 
Lime  is  the  only  available  substance.  Preparations  of  the 
acid  are  sold  under  the  misleading  names  of  salt  of  sorrel, 
and  salt  of  lemon,  and  used  for  removing  ink  stains. 

Cerium  oxalate,  Ce(C2O4)3  -f  9H2O,  is  the  only  salt  of 
oxalic  acid  that  is  used  in  medicine.  It  is  a  permanent 
white  powder;  odorless  and  tasteless. 

Ammonium  oxalate,  (NH4)2C2O4,  forms  white  crystals, 
soluble  in  water,  and  much  used  as  a  test  for  calcium 
compounds. 

Calcium  oxalate,  CaC2O4,  is  colorless  and  insoluble  in 
water.  It  is  usually  found  in  the  urine  in  microscopic 
octohedral  or  dumbbell  crystals.  In  larger  masses  it 
constitutes  mulberry  calculus. 

Experiment  1 7 . — Heat  cautiously  together  in  a  flask  5  grams  of 
sugar  and  40  c.c.  of  nitric  acid.  After  the  reaction  has  ceased 
and  red  fumes  cease  to  be  evolved,  concentrate  the  liquid,  neutral- 
ise with  soda  and  test  for  oxalic  acid,  as  in  the  following  experiment : 

Experiment  18. — Add  a  solution  of  oxalic  acid  to  a  dilute  solu- 
tion of  calcium  chloride  or  to  lime  water  and  observe  the  white 
precipitate  of  calcium  oxalate,  CaC2O4.  Collect  the  precipitate, 
dry  and  ignite  it.  The  residue  is  calcium  carbonate,  CaC2O4  = 
CaCO3  +  CO.  Treat  the  residue  with  acetic  acid  and  note  the 
effervescence. 

Experiment  19. — Prepare  a  dilute  solution  of  potassium  per- 
manganate, add  an  equal  volume  of  solution  of  oxalic  acid,  acidu- 
lated strongly  with  sulphuric  acid,  and  observe  the  discharge  of  color 
of  the  permanganate  solution  according  to  the  following  reaction : 

5H2C2O4  +   K2Mn2O8    +    3H2SO4  =  2MnSO4   +    K2SO4  +  8H2O  + 
ioCO2 

Succinic  Acid,  C2H4(COOH)2. — This  occurs  in  amber 
and  other  resins;  also  in  small  quantities  in  some  animal 
secretions.  It  forms  colorless  crvstals,  soluble  in  water. 


CALIFORNIA   COLLEGE 

of  PHARMACY 

ACIDS  DERIVED  FROM  TRIATOMIC  ALCOHOLS. 

Somewhat  related  to  the  series  just  described,  although 
not  necessarily  referable  to  the  same  radicles,  are  two 
important  vegetable  acids,  malic  and  tartaric.  The 
relation  is  especially  with  succinic  acid,  from  which  they 
differ  only  in  amount  of  oxygen: 

Empirical  formulas. 

Succinic    C4H6O4 

Malic    , C4H6O5 

Tartaric C4H6O6 

Malic  Acid,  H2C4H4O5,  occurs  in  many  sour  fruits,  as 
apples,  pears,  mountain  ash  berries  and  the  fruit  of  Rkus 
glabra.  It  may  be  made  artificially  from  succinic  acid 
by  replacing  an  atom  of  H  with  OH,  or  from  tartaric  acid 
by  reduction  and  removal  of  O.  It  is  crystalline,  sour, 
soluble  in  water  and  alcohol.  The  malates  are  mostly 
soluble  in  water.  Sweet  cherries  contain  potassium 
malate.  The  annexed  formula  will  show  the  presence  of 
asymmetric  carbon  in  malic  acid: 

H       H  H 


AH   A   A 

O=C— C—  C— C=O 


H    H 

Malic  acid 

Tartaric  Acid,  (HO)2C2H2(COOH)2,  is  found  in  many 
plants,  but  especially  in  grapes,  in  which  it  exists  as  acid 
potassium  tartrate,  KHC4H4O6.  This  is  somewhat  soluble 
in  water,  but  insoluble  in  dilute  alcohol;  and  hence,  in  the 
manufacture  of  wine,  as  the  fermentation  advances,  the 

87 


88  ORGANIC    CHEMISTRY. 

quantity  of  alcohol  increases,  and  the  tartrate  deposits  as  a 
red  mass  called  argol  or  tartar.  When  this  is  dissolved  in 
water  and  purified  by  crystallisation  it  constitutes  cream 
of  tartar.  Tartaric  acid  is  obtained  from  argol  by  decom- 
position with  sulphuric  acid.  It  is  the  dextrorotatory 
form  of  four  stereochemic  isomers,  two  of  which  are, 
respectively,  dextro-  and  levorotatory,  and  two  optically 
inactive.  One  of  these  owes  its  inactivity  to  internal 
antagonism  of  the  asymmetric  carbon  atoms,  the  other 
is  a  mixture  of  equivalent  quantities  of  the  two  active 
forms.  By  inoculating  a  solution  of  this  form  with  a 
common  mold  (Penicillium  glaucum)  the  dextrorotatory 
form  is  gradually  broken  up  by  the  organism,  leaving  the 
other  form  unchanged.  This  method  was  discovered  by 
Pasteur  to  whom  the  initial  investigation  in  this  line  is 
due.  There  are  other  methods  of  mesotomy  for  these 
optical  isomers. 

Racemic  acid.  —  This  is  the  naturally  occurring  mixture 
of  the  two  optically  active  forms.  It  is  found  associated 
with  tartaric  acid  and  can  be  prepared  synthetically. 

H   H 

O=C—  C—  C—  C=O 


U 


.  . 

Tartaric  acid 

Acid  potassium  tartrate,  cream  of  tartar,  is  a  white 
crystalline  body,  very  sour,  and  not  very  soluble  in  cold 
water.  It  is  used  in  baking  powders  because  it  liberates 
CO  2  from  alkaline  carbonates  and  acid  carbonates. 


ACIDS    DERIVED    FROM    TRIATOMIC    ALCOHOLS.  89 

Potassium  tartrate,  K2C4H4O6,  is  called  soluble  tartar. 

Sodio- potassium  tartrate,  NaKC4H4O6";  +  4H2O  is  known 
as  Rochelle  salt. 

Tartar  emetic  is  made  by  boiling  acid  potassium  tartrate 
with  antimonous  oxide,  by  which  an  atom  of  hydrogen  is 
replaced  by  the  molecule  SbO.  The  formula  for  tartar 
emetic  is  K(SbO)C4H4O6,  potassium  antimoxyl  tartrate. 
It  crystallises  with  one  molecule  of  water  of  crystallisation 
to  two  molecules  of  the  salt,  the  formula  being  2K(SbO)- 
C4H406+H20. 

Citric  Acid,  (HO)C3H4(COOH)3,  is  the  acid  present  in 
lemons,  limes  and  oranges,  and  is  also  found  in  some  other 
fruits.  It  is  usually  prepared  from  lemons  and  limes, 
which  contain  from  7  to  10  per  cent.,  but  it  has  also  been 
produced  from  solutions  of  cane  sugar  by  the  action  of 
certain  microscopic  fungi.  It  is  normally  present  in  milk. 
It  contains  no  asymmetric  carbon. 

It  is  a  crystalline  body,  very  sour  and  easily  soluble  in 
water,  if  is  used  in  the  preparation  of  effervescing 
mixtures,  but  some  of  the  so-called  effervescing  citrates 
contain  tartaric  instead  of  citric  acid.  At  a  high  tem- 
perature citric  acid  is  decomposed  into  aconitic  acid, 
C3H3(COOH)3  and  H2O. 


H  H  H 

OHO 


J.    JL 

i.i, 


O    H 


H    O 


H— O— C=O 

Citric  acid 


90  ORGANIC    CHEMISTRY. 

METHY-LENE   (METHENYL)   SERIES. 

These  are  triad  radicles.  The  first  member,  CH,  meth- 
enyl,  may  be  regarded  as  existing  in  chloroform.  The 
most  important  member  of  the  group  is  trite nyl,  C3H5,  also 
called  propenyl,  propylene  and  glyceryl.  Its  hydroxide, 
C3H5(HO)3,  is  glycerol.  Many  of  the  common  oils  and 
fats  are  propenyl  esters,  and  when  treated  with  alkalies, 
such  as  sodium  hydroxide,  are  broken  up;  a  new  salt  and 
propenyl  hydroxide  are  formed.  On  propenyl  stearate  (one 
of  the  ingredients  of  common  animal  fat)  sodium  hydrox- 
ide— common  lye — would  act  thus: 

Propenyl  sieaiate.  Sodium  stearate.  Glycerol. 

(C3H5)(C18H3502)3    +    3NaHO    =   3NaC18H35O2    +   C3H5(HO)3 

Sodium  stearate  is  a  soap,  and  the  process  is  saponi- 
fication.  The  formation  of  glycerol  can  also  be  brought 
about  by  the  use  of  superheated  steam.  This  method  is 
now  generally  used,  since  it  gives  the  fatty-adds  in  the 
free  condition,  thus: 

C3H5(C18H3502)3   +   3H20    ==  C3H5(HO)3   +   3HC18H35O2 

Glycerol  (glycerin),  C3H5(HO)3.  —  Pure  glycerol  is  a 
colorless,  viscid  liquid,  miscible  in  all  proportions  with 
water.  Sp.  gr.  1.2659.  It  has  a  sweet  taste,  absorbs 
water  from  the  air,  but  does  not  otherwise  change.  Under 
certain  conditions  of  pressure  it  can  be  distilled  without 
decomposition,  but  under  ordinary  conditions  it  decom- 
poses at  the  boiling  point.  It  solidifies  at  about  — 40°. 
It  dissolves  a  great  many  substances,  standing  next 
to  water  in  its  range  of  solvent  powers.  It  is  produced 
in  small  quantity  during  the  fermentation  of  sugar,  hence 
is  often  found  in  ordinary  liquors.  It  is  sometimes  called 


METHYLENE     (METHENYL)     SERIES.  QI 

the  ''sweet  principle  of  fats,"  but  it  does  not  exist  in 
fats,  and  possesses  no  chemical  analogy  to  them.  It  is 
an  alcohol,  and  is  probably  somewhat  analogous  to  the 
sugars.  Its  use,  therefore,  as  an  application  to  the  skin 
as  a  substitute  for  the  emollient  oils  has  no  chemical 
justification,  and  owing  to  its  strong  affinity  for  water, 
which  it  abstracts  from  the  tissues,  it  often  produces 
irritation  when  applied  in  the  undiluted  state. 

When  treated  with  strong  nitric  acid,  it  forms  propenyl 
nitrate,  C3H5(NO3)3,  known  as  nitro glycerin.  This  is 
a  high  explosive.  It  is  now  extensively  used  as  a  blast- 
ing agent,  being  generally  mixed  with  some  inert  power 
such  as  paper  pulp  or  diatomaceous  earth,  in  which  form 
it  constitutes  dynamite. 


H    H    H 

C— H 


-i.    A  JL    J. 

H-U 


A 


H    H    H 

Glycerol 

FATS  AND  FIXED  OILS. 

The  fats  and  fixed  oils  are  almost  all  esters  of  propenyl 
(glyceryl).  Most  of  the  natural  forms  are  mixtures  of  two 
or  more  distinct  esters.  Names  are  applied  to  them  ac- 
cording to  the  acid  from  which  the  ester  is  derived.  (See 
below.)  The  fixed  oils  are  fats  with  a  low  melting  point, 
and  may  be  divided  into  two  classes;  drying  oils,  which 
absorb  oxygen  from  the  air,  and  become  hard  and  resinous, 


Q2  ORGANIC    CHEMISTRY. 

such  as  linseed  and  poppy  oil;  non-drying  oils,  which 
remain  fluid,  as  castor  and  sperm  oils.  Many  fats  and 
oils  undergo  partial  decomposition  in  the  air,  producing 
acids,  the  condition  being  known  as  rancidity.  When 
an  alkali  is  added  to  a  fat,  decomposition  takes  place,  a 
salt  is  formed,  constituting  a  soap,  and  glycerol  is  pro- 
duced. Soaps  produced  by  potassium  hydroxide  are  usu- 
ally soft;  those  from  sodium  hydroxide  hard  ;  those 
made  from  other  oxides  are  mostly  insoluble  in  water. 
This  latter  fact  explains  the  curdling  action  of  limestone 
waters.  The  calcium  and  magnesium  compounds  in  these 
waters  produce  insoluble  soa'ps.  When  soluble  soaps 
are  treated  with  cold  water  they  decompose  into  acid  salt, 
which  precipitates  and  makes  the  soapsuds,  and  a  basic 
salt,  which  dissolves  and  gives  the  cleansing  action. 

The  fatty-acids  may  be  obtained  by  adding  a  strong 
acid  to  ordinary  soaps. 

The  fats  are  all  insoluble  in  water,  but  are  soluble  in 
ether,  chloroform,  benzene,  petroleum  spirit  and  carbon 
disulphide.  They  are  decomposed  by  heat,  and  conse- 
quently cannot,  under  ordinary  circumstances,  be  dis- 
tilled. 

The  proximate  constituents  of  the  common  fats  are 
given  under  condensed  names,  the  significance  of  which 
is  as  follows: 

Stearin  is  propenyl  stearate. 
Palmitin  is  propenyl  palmitate. 
Margarin  is  propenyl  margarate. 
Butyrin  is  propenyl  butyrate. 
Olein  is  propenyl  oleate. 

Oleic  acid  is  not  a  member  of  the  same  series  with  the 
other  acids.  It  belongs  to  a  series  beginning  with  acrylic 
acid,  C3H4O2,  and  is  elsewhere  described. 


FATS    AND    FIXED    OILS.  93 

Glycero phosphoric  Acids. — Several  of  these  are  possible, 
but  the  only  one  of  importance  is  that  having  the  formula 
C3H5(HO)2H2PO4.  The  structural  formula  of  this  is 
shown  in  connection  with  that  for  lecithin  in  the  section 
on  Proteids.  Some  of  the  complex  esters  that  are  found  in 
higher  tissues,  e.  g.t  brain,  nerve-tissue  and  egg-yolk,  are 
derivatives  of  this  acid.  Calcium,  sodium  and  strychnine 
glycerophosphates  are  used  in  medicine.  The  acid  can  be 
prepared  by  the  action  of  glycerol  on  orthophosphoric  acid. 

Experiment  20. — Heat  together  in  an  evaporating  dish,  40 
grams  of  linseed  oil,  9  grams  of  potassium  hydroxide,  5  c.c.  of 
alcohol  and  50  c.c.  of  water.  *  Continue  the  heat,  with  constant 
stirring,  until  a  small  portion  of  the  mixture  is  found  to  be  com- 
pletely soluble  in  hot  water.  This  process  is  called  saponification 
and  is  analogous  to  the  method  used  in  making  Sapo  mollis  of  the 
Pharmacopoeia.  The  potassium  hydroxide  reacts  with  the  linseed 
oil,  forming  soap  and  glycerol.  By  using  olive  oil  and  sodium 
hydroxide  a  hard  or  soda-soap  is  obtained  which  may  be  precipitated 
from  its  aqueous  solution  by  the  addition  of  sodium  chloride  which 
causes  it  to  separate  in  the  form  of  curdy  masses. 

Experiment  2 1 . — Dissolve  a  small  quantity  of  the  soap  made  in 
the  previous  experiment  in  water,  and  add  it  gradually  to  a  solu- 
tion of  copper  sulphate  (i  to  20).  The  separation  of  an  insoluble 
copper-soap  will  take  place.  The  addition  of  the  soap  solution 
to  a  solution  of  calcium  chloride  will  cause  the  precipitation  of  an 
insoluble  calcium-soap. 

Experiment  22. — Dissolve  about  5  grams  of  soap  in  100  c.c.  of 
water  by  the  aid  of  heat  and  add  to  the  solution  5  c.c.  of  diluted 
sulphuric  acid.  The  fatty-acids  of  the  soap  will  separate  in  the 
form  of  an  oily  layer  upon  the  surface  of  the  liquid. 

Experiment  23. — Heat  about  5  c.c.  of  ethyl  acetate  in  a  flask, 
connected  with  a  reflex  condenser,  with  an  excess  of  sodium  hy- 
droxide (about  4  grams) ,  dissolved  in  a  little  water.  The  odor  of 
ethyl  acetate  disappears  owing  to  saponification  with  the  forma- 
tion of  sodium  acetate  and  alcohol,  according  to  the  following 
reaction : 

C2H5(C2H3O2)    +    NaOH    =    Na(C2H3O2)    +   C2H5OH 


94  ORGANIC    CHEMISTRY. 

Experiment  24. — Melt  about  10  grams  of  butter  in  a  testtube 
by  immersing  it  in  boiling  water;  pour  off  about  2  c.c.  of  the 
melted  butter  into  another  testtube  and  saponify  by  boiling  for 
a  few  moments  with  an  alcoholic  solution  of  sodium  hydroxide. 
After  the  saponification  is  complete,  evaporate  the  solution  to 
dryness  on  the  water  bath  and  redissolve  it  in  a  small  quantity  of 
water.  Add  an  excess  of  dilute  sulphuric  acid  and  heat.  Observe 
the  odor  which  is  evolved.  This  is  due  to  the  volatile  acids  of 
the  butter,  such  as  butyric,  caproic  and  their  homologues;  the 
greater  portion  of  the  fatty-acids  of  the  butter,  being  non- volatile, 
remains  floating  on  the  surface  of  the  liquid  as  an  oily  layer. 

Experiment  25. — Boil  together,  in  an  evaporating  dish,  6.4  grams 
of  lead  monoxide,  12  grams  of  olive  oil  and  5  c.c.  of  water,  re- 
placing the  water  from  time  to  tim£  as  it  is  lost  by  evaporation. 
A  thick  tenacious  compound  is  formed  which  solidifies  upon  cool- 
ing. This  is  the  official  lead  plaster,  lead  oleopalmitate.  Observe 
the  sweetish  taste  of  the  water  with  which  the  compound  has  been 
boiled,  due  to  glycerol  formed  in  the  reaction,  as  follows: 

2(C3H5C18H33O2)3   +  3PbO   +  3H2O 

13302)2   +   2C3H5(HO)3 


Allyl  and  Derivatives. — Allyl,  C3H5,  is  isomeric  with  pro- 
penyl,  but  is  a  monad,  the  carbon  atoms  neutralising  the 
valency  of  each  other  more  completely  than  in  the  case 
of  propenyl.  By  structural  formulas  the  difference  may 
be  thus  represented  : 

Propenyl,  triad.  Allyl,  monad. 

H    H  H  H 

III  II 

— C— C— C— H  C=C— C— 

III  III 

H    H  H    H    H 

Allyl  alcohol  is  C3H5HO.  It  is  obtained  by  the  dis- 
tillation of  glycerol  in  the  presence. of  oxalic  acid  which 
acts  as  a  dehydrolysing  and  reducing  agent.  Allyl  is 
interesting  on  account  of  the  occurrence  in  nature  of  two 
of  its  compounds,  allyl  sulphide,  (C3H5)2S,  which  is  the 


FATS    AND    FIXED    OILS.  95 

essential  oil  of  garlic,  and  allyl  thiocyanate,  C3H5CNS, 
volatile  oil  of  mustard.  Allyl  aldehyde,  C3H4O,  acrolein, 
is  one  of  the  products  of  the  decomposition  of  fats  by  heat, 
and  is  the  main  cause  of  the  irritating  vapors  which  are 
caused  by  such  decomposition.  It  is  formed  by  the  dry 
distillation  of  glycerol  according  to  the  following  reaction : 

C3H5(OH)3    ==  C3H40   +   2H20 

Experiment  26. — Heat  about  5  c.c.  of  glycerol  in  a  dry  testtube 
and  observe  the  irritating  vapors  of  acrolein,  C3H4O,  that  are 
evolved. 

The  oxidation  of  allyl  aldehyde  gives  acrylic  acid,  which 
is  the  first  member  of  a  series  of  acids  derived  from  some 
of  the  fats.  The  most  important  of  this  list  is  oleic  acid. 

Oleic  acid,  C17H33(COOH),  exists  in  most  natural  fats 
and  non-drying  oils  as  olein,  propenyl  oleate.  Above 
15°  it  is  a  clear  liquid,  lighter  than  water,  and  insoluble 
in  it,  but  soluble  in  alcohol  and  ether.  Crude  oleic  acid, 
is  used  in  soap  making,  under  the  name  of  red  oil.  Vari- 
ous oleates,  e.  g.t  copper,  bismuth,  zinc  and  mercury 
oleates,  are  now  used  in  medicine  to  produce  the  physio- 
logical effect  of  the  medicament  by  local  application. 
They  are  usually  prepared  by  the  reaction  of  sodium 
oleate  with  some  suitable  compound.  Thus,  copper 
oleate  is  formed  by  precipitating  solution  of  copper  sul- 
phate with  solution  of  sodium  oleate. 

The  derivatives  of  this  series  are  often  termed  un- 
saturated  compounds  because  they  are  capable  of  taking 
up  negatives  without  substitution  of  hydrogen.  The  latent 
valency  of  the  group  =  C  =  C  =,  which  is  in  all  of  them,  is 
developed.  Iodine  is  especially  adapted  to  this  action  and 
the  proportion  of  it  taken  up  under  specified  conditions 
is  known  as  the  "iodine  number."  It  is  an  important 


96 


ORGANIC    CHEMISTRY. 


datum  in  the  analytic  examination  of  fatty  substances, 
tar  and  petroleum  products.  Some  of  the  fatty  bodies 
containing  these  unsaturated  groups  absorb  oxygen  rather 
rapidly  from  the  air,  becoming  viscous.  This  is  commonly 
termed  "drying"  and  is  a  property  of  the  oils  used  in 
the  preparation  of  paints. 


ACETYLENE  SERIES. 

This  is  a  series  of  unsaturated  radicles  of  which  the  first 
member,  Methine,  is  C.  The  second  member,  Ethine, 
more  commonly  known  as  acetylene,  has  the  formula 
C2H2.  The  structural  formula  may  be  expressed  thus : 

C— H 

III 
C— H 

The  production  of  acetylene  by  the  direct  combination 
of  carbon  and  hydrogen  is  an  example  of  absolute  synthesis, 


CH=CH 


FIG.  10. 


since  both  materials  are  obtainable  from  inorganic  sources. 
The  apparatus  is  shown  in  Fig.  10.  Hydrogen  is  allowed 
to  flow  through  the  flask  while  a  succession  of  electric 


ACETYLENE    SERIES.  97 

sparks  is  passed  through  the  carbon  poles.  Acetylene 
flows  out  at  the  other  opening.  From  acetylene  many 
other  organic  bodies  can  be  made  by  synthesis. 

Other  members  of  the  series,  of  less  importance,  are: 
Allylene  C3H4,  Butine  C4H6,  Pentine  C5H8  and  Hexine 
C6H10.  The  members  of  this  series  are  produced  in  the 
destructive  distillation  of  many  organic  compounds. 
Acetylene  is  produced  by  a  number  of  other  methods, 
involving  the  reduction  of  methane,  ethane,  ethylene,  etc. 
The  incomplete  combustion  of  illuminating  gas,  as  when 
the  flame  in  a  bunsen  burner  or  gas  stove  strikes  back  and 
burns  at  the  base,  yields  some  acetylene.  Acetylene 
is  produced  commercially  for  illuminating  purposes  by 
the  decomposition  of  metallic  carbides  (usually  calcium 
carbide,  CaC2)  with  water.  Acetylene  is  a  colorless  gas 

CaC2    +    2H2O    ==   Ca(HO)2    +    C2H2 

with  a  peculiar  penetrating  odor.  It  burns  with  a  sooty 
flame  from  an  ordinary  burner,  but  with  specially  con- 
structed burners  a  flame  is  produced  which  is  brighter 
and  more  intense  than  the  ordinary  illuminating-gas  flame. 
Acetylene  can  be  liquefied  by  cold  and  pressure.  The 
liquid  is  liable  to  explode.  Acetylene  dissolves  freely  in 
acetone ;  the  solution  is  stated  to  be  not  explosive. 

The  hydrogen  of  acetylene  can  be  replaced  by  strong 
positives  producing  carbides.  The  compounds  formed  by 
members  of  the  potassium  and  calcium  groups  are  stable, 
except  in  presence  of  water  and  alcohol,  but  those  of 
silver  and  copper  are  explosive.  Although  these  com- 
pounds are  simply  carbides,  yet  as  they  are  obtained  by 
reactions  with  acetylene,  an  organic  body,  they  are  classed 
as  organic  compounds.  This  is,  therefore,  an  instance  of 
the  indefiniteness  of  the  term  organic. 
7 


98  ORGANIC    CHEMISTRY. 

The  alcohols  of  this  series  are  but  little  known.  The 
only  one  of  interest  is: 

Propargyl  alcohol,  Propine  hydroxide. — The  structural 
formula  of  this  is  annexed.  It  is  a  mobile  liquid  with  an 
agreeable  odor.  It  forms  silver  and  copper  compounds  by 
exchanging  hydrogen  for  these  elements,  but  not  the 
hydroxyl-hydrogen.  As  with  the  acetylene  derivatives, 
it  is  the  hydrogen  that  is  attached  to  the  triple-linked 
carbon  that  is  replaced. 

H 


H—  C=C—  C—  O—  H 


Propanryl  alcohol 


Experiment  27. — Add  a  small  fragment  of  calcium  carbide,  about 
i  gram,  to  about  500  c.c.  of  water  contained  in  a  large  evaporating 
dish.  Apply  a  lighted  taper  to  the  gas  which  is  evolved  and 
•observe  its  ready  inflammability.  This  gas  is  acetylene.  By 
generating  the  gas  in  a  flask  and  allowing  it  to  pass  into  an  am- 
moniacal  solution  of  cuprous  chloride,  a  reddish-brown  precipitate 
of  copper  carbide  is  formed,  which  is  explosive  when  dry. 

Experiment  28. — Add  a  small  fragment  of  calcium  carbide  to 
about  5  c.c.  of  a  saturated  solution  of  zinc  chloride  contained  in  a 
testtube.  Acetylene  is  not  evolved  as  is  the  case  when  pure  water 
is  used. 


CARBOHYDRATES. 

This  term  was  originally  applied  to  sugars,  starch  and 
allied  bodies,  because  they  contain  carbon,  hydrogen  and 
oxygen,  the  latter  two  being  in  the  proportion  in  which 
they  exist  in  water,  namely,  H2  to  O.  Two  formulas 
will  illustrate  this  : 

Cane  sugar C12H22OU 

Dextrose C6H12O8 

This  limitation  is  now  known  to  be  inapplicable.  Sub- 
stances strictly  analogous  to  the  true  carbohydrates,  and 
exhibiting  other  ratios  of  hydrogen  to  oxygen  have  been 
discovered.  Some  compounds  that  exhibit  this  ratio, 
acetic  acid,  C2H4O2,  for  instance,  are  not  included  in  the 
group.  The  term  is,  however,  too  well  fixed  in  the  nomen- 
clature of  chemistry  to  be  displaced  at  present. 

The  number  of  substances  included  within  this  group  is 
large.  They  are  mostly  of  vegetable  origin,  soluble  in 
water,  optically  active  and  readily  susceptible  to  the  action 
of  enzyms  and  microorganisms,  by  which  they  are  at  first 
usually  hydrolysed  and  then  split  into  simpler  forms, 
changes  that  are  exemplified  in  the  common  forms  of 
fermentation. 

The  group  of  carbohydrates  is  subdivided  as  follows: 

Examples. 

MONOSACCHARIDS Dextrose,  arabinose. 

DISACCHARIDS Sucrose,  lactose. 

TRISACCHARIDS Raffinose. 

POLYSACCHARIDS Starch,  cellulose. 

99 


100  ORGANIC    CHEMISTRY. 

The  carbohydrates  have  moderate  reducing  powers, 
especially  in  alkaline  solution.  Many  of  them  form  with 
phenylhydrazin  characteristic  crystalline  precipitates  called 
"osazones." 

Hydroxyl  is  a  predominating  group  in  the  carbohydrates ; 
several  molecules  are  present  in  even  comparatively  simple 
forms.  They  are,  therefore,  as  a  class,  alcoholic.  They 
break  down  through  the  action  of  certain  fungi,  especially 
yeasts,  into  simpler  bodies  which  are  distinctly  alcoholic, 
such  as  ethyl  alcohol,  some  forms  of  butyl  and  amyl  alcohol, 
and  glycerol.  Methyl  alcohol  does  not  appear  to  be  a  result 
of  these  actions.  Many  carbohydrates  show  feebly  the 
properties  of  acids,  but  they  are  not  true  acids.  Several 
of  the  sugars,  for  instance,  will  form  compounds  with 
calcium  oxide.  A  solution  of  cane  sugar  will  dissolve 
a  notable  amount  of  lime ;  the  compound  formed  has  been 
termed  calcium  saccharate  or  saccharate  of  lime. 

Aldehyde  and  ketone  groups  are  frequently  present  in 
the  carbohydrates.  The  structural  formulas  of  several 
hexoses  are  accurately  known  and  some  of  them  have  been 
obtained  synthetically.  One  of  the  synthetic  methods  is 
by  reactions  between  glycerose  and  formaldehyde.  A 
carbohydrate  that  contains  an  aldehydic  group  is  called 
an  aldose;  a  carbohydrate  that  contains  a  ketone  group 
is  called  a  ketose.  A  carbohydrate  may  contain  all  three 
of  these  groupings,  and  be,  therefore,  aldehydic,  alcoholic 
and  ketonic,  a  condition  that  might  be  condensed  into 
"  aldalcoketose  "  to  show  the  three  types  and  the  carbohy- 
drate structure. 

MONOSACCHARIDS.— Under  the  group  monosaccharids 
are  included  substances  containing  different  numbers  of 
carbon  atoms,  indicated  by  the  terms  monose,  diose, 
triose,  etc.  Of  these  the  pentoses  and  hexoses  are  the 


CARBOHYDRATES.  IOI 

most    important.     Formaldehyde    may    be    considered    a 
monose. 

Glycerose,  C3H6O3,  is  apparently  a  triose,  but  is  a  mixture 
of  two  carbohydrates  obtained  by  the  oxidation  of  glycerol. 
One  of  these  is  an  aldose,  the  first  glycerol  aldehyde,  that  is, 
the  product  obtained  by  removing  H2  from  glycerol  with- 
out introducing  oxygen;  the  other,  a  ketose,  is  the  ketone 
derivative  of  glycerol.  The  formulas  of  these  derivatives 
are,  respectively: 

HCO  HCOH 

HCOH  HCO 

I  I 

H2COH  H2COH 

Aldehyde  Ketone 

Glycerose  is  of  no  practical  interest,  but  its  application 
in  the  synthesis  of  carbohydrates  has  given  it  theoretic 
importance. 

Pentoses  exist  in  many  plant  tissues  and  have  an  impor- 
tant bearing  on  the  nutritive  value  of  vegetable  materials, 
but  the  details  belong  to  physiology  rather  than  chemistry. 

HEXOSES. — Two  important  hexoses  require  detailed 
consideration : 

Dextrose,  Glucose,  Grape  sugar,  C6H12O6. — This  exists 
in  many  fruit  juices  and  in  honey.  It  is  present  in  small 
amount  in  many  animal  fluids  and  excretions;  in  some 
diseases  the  amount  is  greatly  increased.  In  fruit  juices 
and  honey  it  is  associated  with  levulose.  Dextrose  can  be 
obtained  by  the  hydrolysis  of  many  carbohydrates  by 
dilute  acids  or  enzyms.  Starch,  dextrin,  cellulose  and 
cane  sugar  are  easily  hydrolysed  in  this  manner. 

The  principal  commercial  source  of  dextrose  is  by  the 
hydrolysis  of  starch,  usually  corn  starch,  by  dilute  sul- 


102  ORGANIC    CHEMISTRY. 

phuric  acid.  If  the  resulting  solution  is  not  concentrated 
beyond  the  syrupy  condition,  it  will  contain,  in  addition 
to  dextrose,  maltose,  dextrin  and  several  unfermentable 
carbohydrates  not  yet  clearly  isolated.  If  the  material 
be  evaporated  to  solid  form,  it  will  consist  almost  entirely 
of  dextrose.  The  syrupy  liquid  is  commercially  always 
called  "glucose"  and  the  solid  form  "grape  sugar." 

Pure  dextrose  is  a  white,  crystalline  substance,  freely 
soluble  in  water,  to  which  it  imparts  moderate  sweetness. 
The  solution  has  strong  dextrorotatory  power  and  is  easily 
fermentable  by  yeast  into  carbon  dioxide  and  alcohol. 
In  alkaline  solution,  dextrose  has  marked  reducing  power, 
liberating  copper,  lead,  silver,  gold  and  platinum  from 
their  compounds.  It  forms  with  phenylhydrazin  an 
osazone  that  crystallises  in  yellow  stellate  tufts. 

Commercial  glucose  is  largely  used  as  a  substitute  for 
other  carbohydrates  in  the  fermentation  industries,  and 
also  as  a  substitute  and  adulterant  for  honey,  molasses  and 
maple  syrup. 

Levulose,  C6H12O6,  d-Fructose,  Fruit  sugar. — This  is 
associated  with  dextrose  in  fruit  juices  and  in  honey,  and 
is  produced  in  equal  amount  with  dextrose  in  the  hydrolysis 
of  sucrose.  It  can  be  obtained  pure  by  heating  inulin  with 
water  at  the  boiling  point  for  twenty-four  hours. 

Levulose  is  soluble  in  water,  forming  a  sweet  liquid  that 
is  strongly  levorotatory  at  ordinary  temperatures;  less  so 
when  hot.  It  ferments  with  yeast  to  carbon  dioxide 
and  alcohol,  but  not  so  readily  as  dextrose,  hence  many 
fruit-juices,  become  levorotatory  when  fermented,  the 
dextrose  being  removed  much  faster  than  the  levulose. 

Notwithstanding  the  strong  levorotatory  power  of 
ordinary  levulose,  it  is,  on  account  of  certain  structural 
relations,  usually  termed  d-fructose. 


CARBOHYDRATES.  103 

Ordinary  dextrose  and  levulose  are  alcohols,  but  are  not 
stereo-isomers.  The  former  is  an  aldehyde,  the  latter  is  a 
ketone.  There  is,  therefore,  a  form  of  dextrose  having 
left-handed  rotation  and  one  of  levulose  having  right- 
handed  rotation;  in  fact,  theory  indicates,  and  research 
has  confirmed,  the  existence  of  numerous  isomeric  hexoses 
and  derivatives.  The  annexed  formulas  show  the  struc- 
ture of  some  of  these  bodies.  Asymmetric  carbon  is  present 
in  all.  In  forming  osazones,  dextrose  and  levulose  lose 
the  characteristic  groupings,  that  is,  dextrose  loses  the 
aldehyde  group  and  levulose  loses  the  ketone  group. 
Hence  these  hexoses,  though  not  stereo-isomers,  yield  the 
same  osazone. 

H  H 

H— O— C— H  H— O— C— H 

H— O—  C— H  0=C 

H— O— C— H  H— O— C— H 

H— O— C— H  H— O— C— H 

H— O— C— H  H— O— C— H 

O=C  H— O— C— H 

A  A 

Dextrose  Levulose 


104  ORGANIC    CHEMISTRY. 

H  O 

I  II 

O=C  H— O— C 

H— O— C— H  H— C— O— H 

H— O— C— H  H— C— O— H 

H— O— C— H  H— C— O— H 

H— O— C— H  H— C— O— H 

C  =  O  H— O— i 

6  !l 

A 

Glycuronic  acid  Saccharic  and  Mucic  acids 

It  will  be  noted  that  glycuronic  acid  is  an  alcohol, 
aldehyde  and  acid.  Saccharic  and  mucic  acids  which 
are  products  of  oxidation  of  several  carbohydrates  and 
stereo-isomers ,  are  alcoholic  and  acid  only. 

HEXOSE  ALCOHOLS. — These  contain  hydroxyl  groups 
but  no  aldehydic  nor  ketonic  groups.  They  resemble 
the  ordinary  hexoses  in  many  ways  but  do  not  reduce 
Fehling's  solution  and  are  not  fermented  by  yeast.  The 
most  important  is : 

Mannite,  Mannitol,  C6H14O6,  which  is  seen  not  to  cor- 
respond in  its  empirical  formula  to  the  ordinary  definition 
of  a  carbohydrate.  Mannite  exists  in  three  isomeric 
forms,  dextro-  and  levorotatory  and  inactive.  The  dextro- 
rotatory 'form  is  a  natural  product,  occurring  in  several 
plants,  especially  in  the  manna,  an  exudation  from  Fraxi- 


CARBOHYDRATES.  105 

nits  ornus.  It  may  be  prepared  synthetically  by  the  action 
of  sodium  amalgam  upon  levulose. 

Sorbite,  from  mountain  ash  berries,  and  dulcite,  from  a 
manna  from  Madagascar,  are  similar  in  composition  to 
mannite.  Care  must  be  taken  not  to  mistake  the  ter- 
mination in  these  names  for  the  syllable  used  in  the  names 
of  some  salts.  The  terms  sorbitol  and  dulcitol  would  be 
preferable  for  these  bodies. 

DISACCHARIDS. — Sucrose,  Cane  sugar,  C12H22OU. — This 
exists  in  the  juices  of  many  plants,  but  is  commercially 
obtained  from  few  sources:  sugar-cane,  beet -root,  maple 
and  sorghum.  It  is  a  colorless  solid,  easily  crystallised 
and  very  soluble  in  water.  The  solution  is  very  sweet  and 
has  high  dextrorotatory  power.  It  does  not  reduce 
Fehling's  solution,  nor  form  a  precipitate  with  phenyl- 
hydrazin.  It  ferments  readily  with  yeast,  but  this  effect 
is  preceded  by  a  hydrolysis  under  the  influence  of  an 
enzym  present  in  the  yeast-cell.  By  this  hydrolysis,  one 
molecule  of  sucrose  takes  up  one  molecule  of  water,  and 
divides  into  one  molecule  of  dextrose  and  one  of  levulose. 
The  equation  of  the  reaction  is : 

C12H220U    +   H20    ==   C6H1206    +   C6H1206 

The  proportions  by  weight  are  95  parts  of  sucrose  to  5 
parts  of  water,  yielding  50  parts  of  dextrose  and  50  parts  of 
levulose.  As  the  specific  rotatory  power  of  levulose  is,  at 
ordinary  temperatures,  higher  than  that  of  dextrose,  the 
resulting  mixture  is  slightly  levorotatory,  and  is  termed 
"invert  sugar."  The  same  transformation  can  be  brought 
about  by  the  action  of  dilute  acids  and  many  mineral 
salts.  It  is  technically  known  as  an  "inversion."  The 
yeast-enzym  that  inverts  sucrose  is  called  "invertase." 
The  fermentation  that  ensues  is  produced  by  other  en- 


106  ORGANIC    CHEMISTRY. 

zyms  not  yet  definitely  isolated,  and  affects  the  dextrose 
more  actively  than  the  levulose. 

Maltose,  C12H22On,  is  produced  together  with  dex- 
trins  by  the  action  of  common  enzyms  on  starch.  It  is 
abundantly  present  in  malt.  It  is  sweet,  soluble  in  water, 
readily  fermentable  with  yeast,  reduces  Fehling's  solution 
and  forms  a  characteristic  osazone. 

Lactose,  C12H22OU,  is  the  characteristic  carbohydrate 
of  cow's  milk.  It  probably  exists  in  the  milk  of  many 
other  animals.  Richmond  obtained  from  the  milk  of  a 
species  of  buffalo,  domesticated  in  Egypt,  a  similar  body 
to  which  he  gave  the  name  "tewfikose." 

Ordinary  lactose,  obtained  from  the  whey  of  cow's  milk, 
crystallises  in  colorless,  gritty  masses  moderately  soluble 
in  cold  water  and  with  slight  sweetness.  The  solution 
ferments  readily  to  lactic  acid,  but  yields  alcohol  only  under 
the  influence  of  special  ferments.  In  alkaline  solution, 
lactose  reduces  compounds  of  silver  and  copper  promptly. 
It  yields  a  characteristic  osazone  and  differs  from  sucrose 
in  not  being  carbonised  by  strong  sulphuric  acid,  and  in 
reducing  Fehling's  solution. 

The  principal  medicinal  use  of  lactose  is  in  the  prepara- 
tion of  tablets  and  triturates  of  powerful  drugs.  In  its 
ordinary  form  it  is  associated  with  one  molecule  of  water 
of  crystallisation,  which  may  be  driven  out  by  gentle 
heating.  A  freshly  made  solution  in  water  shows  excep- 
tionally high  optical  activity  (termed  ' '  birotation  " )  but  on 
standing  for  some  hours,  or  promptly  on  boiling,  the  normal 
rotating  power  is  developed.  Boiling  with  sulphuric  acid 
slowly  hydrolyses  lactose  into  a  mixture  of  equal  parts  of 
two  hexoses,  ordinary  dextrose  and  galactose. 

The  TRISACCHARID,  Raffinose,  is  found  in  association  with 
beet  sugar. 


CARBOHYDRATES.  IOJ 

POLYS  ACCHARIDS. — Cellulose,  wC6H10O5  is  the  colorless 
material  of  woody  fibre.  It  is  seen  in  cotton  or  linen  in  a 
nearly  pure  form.  It  dissolves  in  an  ammoniacal  solution 
of  cupric  hydroxide  but  is  insoluble  in  water,  ether  or 
alcohol.  Strong  sulphuric  acid  converts  it  either  into  a 
soluble  substance,  like  dextrin,  or  into  a  substance,  giving 
a  blue  color  with  iodine.  By  long-continued  action  of 
dilute  sulphuric  acid,  cellulose  is  converted  into  dextrose. 

Paper  is  nearly  pure  cellulose  obtained  by  boiling  vege- 
table structures  with  solutions  that  dissolve  the  cementing 
materials.  For  the  best  grades  of  paper,  made  from 
linen  and  cotton,  weak  solutions  of  sodium  hydroxide  in 
open  vessels  are  used,  but  much  paper  is  made  from  wood, 
by  boiling  with  strong  solutions  of  sodium  hydroxide  or 
magnesium  sulphite  under  pressure.  The  inferior  grades 
of  commercial  paper  contain  much  ground  wood  not 
chemically  treated. 

When  paper  is  treated  for  a  short  time  with  a  cold 
mixture  of  two  volumes  of  sulphuric  acid  and  one  of  water, 
it  becomes  tough  and  waterproof,  and  is  termed  parchment 
paper. 

Cellulose  may  be  dissolved  and  reprecipitated.  By 
mechanical  methods  the  precipitate  may  be  obtained  in 
threads  or  thin  sheets,  thus  producing  artificial  textile 
materials. 

Pyroxylin,  Gun-cotton. — Cellulose  yields  with  nitric 
acid  a  series  of  nitric  esters,  having  explosive  properties. 
The  composition  differs  with  the  strength  of  the  acid, 
temperature  and  time  of  immersion.  All  the  products 
retain  the  general  physical  appearance  of  the  original 
material,  but  become  rapidly  combustible,  burn  with  a 
bright  smokeless  flame  disengage  much  gas,  and  leave  no 
appreciable  residue.  They  dissolve,  or  gelatinise,  in 


108  ORGANIC    CHEMISTRY. 

liquids  which  do  not  affect  cellulose.  When  the  degree 
of  nitration  is  low,  e.  g.,  the  composition,  wC6H8(NO2)2O5, 
the  product  is  soluble  in  a  mixture  of  alcohol  and  ether 
and  is  called  soluble  or  negative  cotton.  The  latter  term 
refers  to  its  use  in  preparing  photographic  negatives. 
When  the  formula  contains  larger  proportions  of  the 
nitric  acid  radicle,  the  material  is  highly  explosive,  less 
soluble  and  is  known  as  gun-cotton.  It  is  used  alone  as  an 
explosive  and  also  in  the  preparation  of  smokeless  powders. 

Collodion  is  formed  by  dissolving  pyroxylin  in  a  mixture 
of  ether  and  alcohol.  This  is  called  plain  collodion. 

Celluloid  is  a  mixture  of  pyroxylin  and  camphor. 

Glycogen. — This  is  an  animal  product  and  is  a  white, 
amorphous  powder,  which  gives  a  brown  color  with  iodine 
and  by  the  action  of  ferments  or  dilute  acids  is  converted 
into  dextrose.  It  therefore  resembles  starch,  but  is  solu- 
ble in  cold  water. 

Starch. — This  term  is  applied  to  a  carbohydrate  found 
widely  distributed  in  the  vegetable  kingdom,  in  different 
tissues,  but  especially  seeds,  rhizomes  and  tubers.  It  is 
intimately  connected  with  the  formation  of  the  cellular 
structure  of  vegetables.  The  conditions  of  its  develop- 
ment have  been  carefully  studied  owing  to  its  importance 
in  vegetable  physiology.  It  is  not  unlikely  that  the  first 
step  in  its  formation  is  the  synthesis  of  formaldehyde 
under  the  influence  of  sunlight  in  accordance  with  the 
following  equation: 

CO2   +   H2O    =  CH20   +   O 

From  the  formaldehyde,  by  polymerisation,  complex 
carbohydrates  and  finally  starch  is  produced. 

The  percentage  composition  of  starch  corresponds  to  the 
empirical  formula  C6H10O5;  the  molecular  weight  is  un- 


CARBOHYDRATES.  IOQ 

known  but  is  certainly  high.  The  rational  formula  is  also 
unknown. 

Starch  is  deposited  in  the  cells  of  plants  in  minute 
granules  which  are  sufficiently  characteristic  in  form  to 
permit  the  source  of  the  starch  to  be  recognised  by  micro- 
scopic examination.  In  most  cases,  the  granules  are  spher- 
ical or  spheroidal.  They  are  often  marked  by  concentric 
rings  and  by  a  spot,  termed  the  hilum. 

Starch  is  not  appreciably  soluble  in  cold  water;  hot 
water  breaks  up  the  granules,  dissolves  some  of  the  material 
and  forms  with  the  remainder  a  jelly  of  very  low  diffusive 
power.  The  solution  has  high  dextrorotatory  power. 
With  free  iodine,  starch  produces  a  deep  blue  compound, 
sometimes  called  starch  iodide,  but  the  exact  nature  of  it 
is  not  known.  It  is  dissociated  by  heating  the  liquid,  the 
mixture  becoming  colorless,  but  the  color  returns  on  cool- 
ing. The  solid  starch  also  gives  the  blue  with  iodine. 

Many  enzyms,  especially  those  of  malt,  saliva  and  pan- 
creatic secretion,  quickly  convert  starch -jelly  by  hydrolysis 
into  a  mixture  of  maltose  and  dextrin.  Dilute  acids  also 
hydrolyse  starch,  producing  much  dextrose  with  some 
dextrin. 

Inulin  is  a  carbohydrate  that  exists  in  the  roots  of  many 
Compositae,  such  as  dahlia  and  chicory.  By  boiling  with 
water  for  some  time  it  is  completely  converted  into  levulose. 

Dextrin. — This  term  includes  several  substances  that 
have  not  been  clearly  distinguished.  Their  composition 
corresponds  to  the  formula  nC6H10O5.  They  are  produced 
from  starch  by  direct  heating  with  water  and  by  hydrolysis 
with  dilute"  acids  and  many  enzyms.  They  are  amor- 
phous, light  yellow  powders,  insoluble  in  alcohol,  soluble 
in  water,  forming  an  adhesive  mucilage.  The  solution  is 
strongly  dextrorotatory  and  does  not  reduce  Fehling's 


HO  ORGANIC    CHEMISTRY. 

solution.  By  boiling  with  dilute  acids,  the  dextrin  may 
be  converted  into  dextrose. 

The  dextrin  obtained  by  heating  starch  with  water 
under  pressure  is  sometimes  called  British  gum.  It  is 
used  as  an  adhesive. 

Gum  Arabic,  an  exudation  from  species  of  Acacia, 
consists  chiefly  of  the  calcium  and  magnesium  arabates. 
It  is  used  in  the  preparation  of  mucilage. 

Gum  Tragacanth. — This  is  composed  of  several  carbo- 
hydrates, some  of  which  are  soluble  in  water  and  others 
that  do  not  dissolve,  but  absorb  water  in  large  amount  and 
swell,  making  an  adhesive  paste. 

Several  vegetable  gelatinising  materials,  such  as  agar- 
agar,  are  probably  carbohydrates  or  closely  related  to 
them. 

Experiment  29. — Prepare  starch  solution  as  follows:  (Arrow-root 
starch  is  best  but  corn  starch  will  serve.)  Fifty  c.c.  of  water 
are  brought  to  the  boiling  point ;  a  few  grams  of  starch  are  stirred 
well  with  10  c.c.  of  cold  water  and  this  mixture  poured  into  the 
boiling  water  with  constant  stirring.  The  liquid  is  allowed  to 
become  quite  cold.  Portions 'of  about  10  c.c.  are  used  for  the 
experiments. 

Experiment  30. — Test  a  portion  of  the  starch  solution  with  solu- 
tion of  potassium  iodide;  no  color  will  appear.  Add  a  few  drops 
of  solution  of  iodine;  a  blue  color  at  once  appears.  Heat  the 
mixture  just  to  boiling;  it  will  become  paler  or  colorless,  and  on 
cooling  the  color  will  return.  The  compound  formed  by  the 
starch  and  iodine  is  apparently  dissociated  by  heat. 

Experiment  31. — Add  to  a  portion  of  the  starch  solution  a  small 
amount  of  either  diastase,  takadiastase,  pancreatic  extract  or 
saliva,  and  allow  the  mixture  to  stand  for  a  few  moments.  Test 
portions  of  about  i  c.c.  every  few  minutes  with  iodine  solution. 
The  starch  reaction  will  soon  be  replaced  by  a  dark,  brownish 
color,  which  will  soon  be  followed  by  a  reddish  brown,  indicating 
the  completion  of  the  hydrolysis.  (See  under  "  Enzyms.") 

Experiment  32. — Add   10  c.c.  of  the  starch  solution  to   10  c.c. 


CARBOHYDRATES.  Ill 

of  water  and  a  few  drops  of  sulphuric  acid.  Boil  the  mixture  for 
five  or  ten  minutes,  cool,  add  slaked  lime  in  small  portions  until 
litmus  paper  is  not  reddened  by  the  liquid,  filter  and  test  for 
reducing  sugar  as  noted  below. 

Experiment  33. — Treat  starch  solution  with  any  one  of  the 
enzyms  noted  in  Experiment  31  and  test  the  resulting  mixture 
for  reducing  sugar. 

Experiment  34. — Make  separate  solutions  of  sucrose,  dextrose 
and  lactose  by  dissolving  about  5  grams  of  each  in  50  c.c.  of  water. 
The  water  may  be  heated  if  necessary  to  hasten  the  solution,  but 
should  be  allowed  to  cool.  For  the  dextrose  solution,  the  common 
glucose  or  grape-sugar  will  answer.  Portions  of  10  c.c.  of  each  of 
these  should  be  taken  for  the  experiment.  Each  experiment  given 
below  should  be  repeated  with  each  sugar. 

Experiment  35. — Test  the  reducing  action  by  boiling  with  copper 
sulphate  rendered  alkaline  with  sodium  hydroxide  solution. 

Experiment  36. — Test  the  action  by  boiling  with  a  pinch  of  bis- 
muth subnitrate  and  sodium  hydroxide  solution. 

Experiment  37. — Test  the  reducing  action  with  solution  of 
silver  nitrate  rendered  alkaline  with  ammonium  hydroxide. 

Experiment  38. — Make  a  solution  of  10  grams  of  sucrose  in  100 
c.c.  of  water,  and  divide  it  into  two  approximately  equal  portions. 
Grind  a  cake  of  fresh,  compressed  yeast  with  20  c.c.  of  water, 
filter  the  liquid  and  add  one-half  the  filtrate  to  each  of  the  su- 
crose solutions.  To  one  of  the  solutions  also  add  a  few  drops  of 
a  strong  alcoholic  solution  of  thymol,  and  a  drop  of  acetic  acid. 
Place  both  solutions  in  flasks  and  keep  them  for  twenty-four  hours 
at  a  temperature  between  35°  to  40°.  The  flasks  may  be  loosely 
stopped  with  a  little  cotton  wool  or  by  covering  with  watch-glasses. 
They  should  not  be  tightly  stopped.  The  solution  containing  the 
thymol  will  be  converted  into  invert-sugar  without  fermentation; 
the  other  solution  will  soon  begin  to  ferment,  give  off  carbon  dioxide 
and  form  alcohol.  Both  solutions  will  acquire  levorotatory  power. 

Experiment  39. — Make  a  solution  of  sucrose  containing  about 
5  grams  in  100  c.c.;  add  i  gram  of  citric  acid  and  boil  the  liquid 
for  ten  minutes,  replacing  the  water  as  it  is  lost.  Allow  the  solu- 
tion to  cool  and  examine  it  for  invert-sugar  by  any  of  the  standard 
tests,  such  as  reduction  of  Fehling's  solution,  reduction  of  bismuth 
subnitrate,  formation  of  osazone  by  phenylhydrazin  or  rotatory 
power. 


112  ORGANIC  CHEMISTRY. 

GLUCOSIDES. 

This  term  includes  a  large  number  of  substances,  mostly 
of  vegetable  origin,  that  are  easily  decomposed  into  several 
simpler  bodies,  one  of  which  is  dextrose  or  an  analogous 
carbohydrate.  Dilute  acids  and  some  enzyms  are  the 
usual  means  of  producing  these  changes,  the  action  is, 
in  most  cases,  by  hydrolysis.  A  glucoside  may,  therefore, 
be  regarded  as  an  'ester  of  the  carbohydrate  yielded  by  it. 

Most  glucosides  are  non-nitrogenous.  Many  are  the 
active  principles  of  the  plants  in  which  they  occur,  but  in 
some  cases  this  activity  is  due  to  the  products  of  decom- 
position and  not  to  the  glucoside  itself.  This  is  the  case 
with  mustard,  bitter  almonds  and  wild  cherry  bark.  As 
a  rule,  the  glucosides  are  associated  with  the  enzym 
necessary  for  their  decomposition.  Starch  and  some  of  the 
other  carbohydrates  may  be  regarded  as  glucosides  as  they 
yield  dextrose  by  hydrolysis. 

Amygdalin,  C2QR27^O11J  exists  in  tissues,  especially  seeds, 
of  many  plants  of  the  order  Rosaceae,  in  association  with  an 
enzym  called  synaptase.  This  acts  on  the  amygdalin, 
when  the  seeds  are  crushed  in  cold  water;  but  boiling 
alcohol  coagulates  the  synaptase  and  dissolves  the  unde- 
composed  amygdalin.  The  latter  is  a  white,  crystalline 
body,  soluble  in  alcohol  and  water,  but  not  in  ether.  The 
decomposition  to  which  it  is  susceptible  is  explained  in 
connection  with  the  description  of  hydrogen  cyanide. 

Salicin,  C13H18O7,  is  found  principally  in  the  bark  and 
leaves  of  the  poplar  and  willow.  It  crystallises  in  white 
needles;  insoluble  in  ether,  but  soluble  in  water  and  alco- 
hol. Salicin  decomposes  as  follows: 

C13H1807    +    H20    «   C7H802    +   C6H120C 
C7H8O2  is  called  saligenin. 


GLUCOSIDES.  113 

The  structural  formula  of  salicin  shows  open  and  closed 
chains.  The  significance  of  the  hexagon  is  explained  under 
Benzene.  The  structure  of  dextrose  is  also  evident,  and 
a  methyl  ether  group  (H3C — O)  is  present. 


I 

C 


H  HH 

v 

—  C—  O—  H 

H    H     H     H 

fill 
0 


H3C—  O^    )      00000 
^  ' 


I       I       I       I 
C—C—  C—  C—  C—  H 

ill 
H    H     H     H 


Tannins. — These  are  astringent  principles,  widely  dif- 
fused in  the  vegetable  kingdom.  They  dissolve  in  water 
and  have  an  acid  reaction;  hence  are  often  called  tannic 
acids.  Many  forms  are  known;  they  possess  the  common 
property  of  precipitating  gelatin  and  giving  dark-colored 
precipitates  with  ferric  salts.  Their  action  on  gelatin 
is  utilised  in  the  preparation  of  leather,  and  their  action 
with  ferric  salts  in  making  ink. 

Ordinary  tannin,  gallo-tannic  acid,  occurs  in  nutgalls — 
excrescences  formed  on  a  species  of  oak  by  puncture  by  an 
insect — and  sumach.  It  is  usually  seen  as  a  loose,  brittle, 
light-yellow,  non-crystalline  mass,  very  soluble  in  water 
and  highly  astringent.  It  gives  a  bluish-black  precipitate 
with  ferric  salts.  The  common  form  is  not  entirely  a 
glucoside  but  contains  a  large  amount  of  digallic  acid, 
C14H10O9. 

When  tannin  is  boiled  with  dilute  acids,  or  mixed  with 
water  and  exposed  to  moist  air,  it  forms  gallic  acid  by 
hydrolysis  of  the  glucoside  or  digallic  acid. 


114  ORGANIC    CHEMISTRY. 

Thus :— 

Tannin  (glucoside).  Dextrose.  Gallic  acid. 

C27H22017    +   4H20    =   C6H1206    +    3C7H605. 

Digallic  acid.  Gallic  acid. 

C14H1009    +    H20    .   2C7H605. 

The  formation  of  gallic  acid  is  a  loss  in  the  manufacture 
of  leather,  since  it  has  no  tanning  qualities.  The  change 
can  be  prevented  by  antiseptic  substances,  such  as  sulphur- 
ous and  boric  acids,  and  solutions  of  these  are  sold  under 
the  name  of  .antigalline.  The  process  of  tanning  consists 
essentially  in  the  tannin  rendering  the  gelatinous  matter  of 
the  hide  insoluble,  and  therefore  not  liable  to  decomposi- 
tion. 

Sinigrin,  Potassium  Myronate,  KC18H10NS2O10. — The 
seed  of  the  black  mustard  contains  this  body  and  also 
an  enzym,  myrosin,  which  decomposes  the  sinigrin  accord- 
ing to  the  following  equation : 

KC10H18NS2010    ==  C3H5CNS    +   C6H12O6   +    KHSO4. 

C3H5CNS  is  allyl  thiocyanate,  to  which  the  irritating 
action  of  mustard  is  due.  Preparations  of  it  should  not  be 
made  with  hot  water  as  this  will  injure  the  enzym  and 
prevent  the  decomposition.  It  will  be  noted  that  this  is 
not  hydrolysis.  By  direct  action  of  amine,  allyl  thiocya- 
nate is  converted  into  thiosinamin  (allyl  thiocarbamide). 

White  mustard  seed  contains  a  glucoside,  sinalbin,  and 
an  enzym,  myrosin. 

Indican,  C52H62O34,  occurs  in  several  plants,  especially 
those  of  the  genus  Indigofera.  By  boiling  with  acids  it 
yields  the  color  known  as  indigo  blue  (indigotin).  Indigo 
blue  is  obtained  from  the  plants  containing  indican, 
by  macerating  them  with  water,  and  exposing  to  the  air 
until  fermentation  occurs  and  blue  is  deposited. 


Cyclic  Hydrocarbons. 

In  these  compounds,  carbon  atoms  are  connected  into 
one  or  more  closed  series  or  chains.  Three  is  the  smallest 
number  of  atoms  that  can  form,  such  a  chain.  When  the 
chain  is  composed  of  one  kind  of  atoms,  the  molecule  is 
honiocyclic  or  isocyclic.  This  term  is  generally  applied  to 
carbon  chains,  although  obviously  not  necessarily  so 
limited.  The  nucleus  of  three  nitrogen  atoms  in  azoimide 
is  homocyclic.  As  with  the  open-chain  compounds, 
some  of  the  valencies  may  be  latent,  that  is,  two  atoms 
may  be  connected  by  more  than  one  bond.  These  latent 
valencies  are  developed  only  under  special  conditions, 
giving  origin  to  additive  compounds. 

When  the  chain  includes  atoms  of  different  elements,  it 
is  termed  keterocyclic .  The  more  important  instances  of 
this  arrangement  are  rings  containing  two  or  more  carbon 
atoms  linked  with  an  atom  of  oxygen,  sulphur  or  nitrogen. 

These  closed-chain  compounds  may  have  the  same 
empirical  formula  as  open-chain  compounds.  The  former 
are,  therefore,  not  infrequently  named  by  attaching  the 
prefix  "c'yclo"  to  the  name  of  the  open-chain  compounds. 
Thus,  trimethene  (CH2)3,  isomeric  with  C3H6,  propane, 
is  called  ''cyclopropane." 

HOMOCYCLIC  COMPOUNDS. 

Of  all  these  series,  the  most  important  and  interesting, 
both  from  practical  and  theoretic  points  of  view,  is  the  six- 


Il6  ORGANIC    CHEMISTRY. 

carbon  homocyclic  series,  commonly  termed  the  Benzenes, 
from  the  name  of  the  fundamental  hydrocarbon.  It  will 
be  sufficient  to  note  a  few  points  in  regard  to  other  groups. 
Three-membered  Rings. — An  instance  of  this  is  found  in 
cyclopropane,  trimethylene  or  trimethene,  isomeric  with 
propane,  the  difference  in  structure  being  shown  in  the 
annexed  formulas: 

H    H    H 

I       I       I  H2C 

H— C— C— C— H  |    >CH2 

i  A  A 

Propane  Cyclopropane 

Four -member  ed  Rings. — The  compounds  of  this  type 
have  as  yet  but  little  practical  interest.  Methyl  tetrame- 
thene,  i(CH2)3CH(CH3),  is  an  instance. 

Five -member  ed  Rings. — A  considerable  number  of  deri- 
vatives of  this  type  are  known.  Common  camphor  yields 
methene  derivatives  of  this  type,  but  the  reactions  by 
which  these  are  produced  are  not  yet  known. 

Seven-membered  rings  are  also  known  but  they  tend  to 
reduce  to  six-carbon  rings. 


SIX-CARBON  HOMOCYCLIC  COMPOUNDS. 

Three  subgroups  of  these  are  distinguished: 

Benzenes  (aromatic  hydrocarbons). 
Terpenes  (essential  oils). 
Polynucleated  compounds. 


BENZENES. 

Historical   Note. — In   the   manufacture   of   illuminating-gas   by 
the  destructive  distillation  of  bituminous  coal  and  shale  and  in 


COLLEGE 

of  PHARMACY 

BENZENES.  117 

the  manufacture  of  coke,  many  products  are  obtained,  some  gaseous 
at  ordinary  temperatures,  others  liquid  and  solid.  The  liquid  and 
solid  bodies  are  collected  in  mixture  as  a  dark,  thick  liquid,  with 
an  odor  recalling  that  of  the  gas.  This  is  known  as  coal-tar.  For 
a  long  while  it  was  a  useless  by-product  and  its  disposal  a  serious 
problem.  In  1825  Faraday  obtained,  by  compressing  coal  gas,  a 
hydrocarbon,  which  is  now  known  to  be  identical  with  that  ob- 
tained by  Mitscherlich  in  1834,  by  distilling  calcium  benzoate, 
which,  on  account  of  this  source,  was  called  "benzene."  In  1845 
Hofmann  discovered  the  same  body  in  coal-tar,  and  not  long  after- 
wards, Mansfield,  a  pupil  of  Hofmann,  prepared  it  in  practicable 
quantity  from  the  tar.  Mansfield  lost  his  life  while  preparing  a 
sample  for  public  exhibition. 

Experiments  with  benzene  soon  showed  that  it  is 
capable  of  yielding  many  derivatives,  and  while  showing 
no  isomeric  modifications  itself,  its  derivatives  show  many 
instances  thereof.  The  chemical  nature  of  benzene  was 
imperfectly  understood  up  to  1865,  when  Kekul6  suggested 
that  its  molecule  consists  of  six  carbon  atoms  in  a  closed 
chain  with  six  latent  valencies  and  six  other  valencies 
satisfied  by  hydrogen.  By  this  theory,  so  far,  all  the 
numerous  derivatives  can  be  formulated  consistent  with 
their  isomerisms  and  relations.  Moreover,  the  properties 
of  benzene  itself  are  explained  by  the  theory.  Benzene 
ordinarily  exhibits  the  functions  of  a  saturated  hydrocar- 
bon, but,  under  special  conditions,  it  is  capable  of  forming 
additive  compounds,  this  addition  taking  place  by  the 
simultaneous  action  of  two  valencies. 

Kekule's  view  has  been  generally  accepted,  and  ex- 
tended to  many  other  classes  of  compounds.  Some 
difference  of  opinion  exists  as  to  the  manner  in  which  the 
latent  valencies  are  disposed,  but  it  is  not  necessary  to 
discuss  this  point. 

Coal-tar  contains  many  substances  that  are  structurally 
related  to  benzene;  these  may  be  separated,  but  usually 


Il8  ORGANIC    CHEMISTRY. 

somewhat  imperfectly  by  fractional  distillation.  It  is 
known  that  benzene  obtained  from  tar,  unless  especially 
purified,  contains  a  compound  in  which  sulphur  takes  the 
place  of  two  carbon  atoms.  This  will  be  noted  under  the 
heterocyclic  compounds.  Among  the  important  bodies 
associated  with  benzene  in  coal-tar,  are  toluene,  phenol, 
anthracene,  naphthalene  and  pyridin.  The  benzene  oc- 
curs in  the  most  volatile  portion  of  the  tar,  termed  light 
oils.  Crude  benzene  is  known  in  commerce  as  "benzol," 
a  name  which  has,  unfortunately,  been  much  used  for  ben- 
zene itself. 

Benzene,  phene,  C6H6,  is  a  colorless  mobile,  volatile 
liquid  with  an  odor  that  suggests  coal-tar.  It  melts  at 
5.4°  and  boils  at  80.4°.  The  solid  benzene  resembles 
common  paraffin.  The  sp.  gr.  of  the  liquid  is  0.8.99.  It 
has  high  solvent  powers  for  many  substances,  notably  fats, 
waxes  and  resins.  It  is  readily  inflammable,  burning  with 
a  smoky  flame,  but  does  not  undergo  direct  oxidation  by 
ordinary  oxidising  agents.  Benzene,  as  already  noted, 
forms  two  classes  of  derivatives,  additive  and  substitutive. 
The  former  are  of  little  practical  interest,  but  the  latter  are 
very  numerous  and  important.  Additive  compounds  of 
monad  elements  are  formed  with  even  numbers  of  atoms, 
e.  g.,  benzene  chlorides  are  C6H6C12;  C6H6C14;  C6H6C16. 
The  substitution  of  monad  elements  or  radicles  may  take 
place  singly,  chlorbenzenes,  C6H5C1;  C6H4C12;  C6H3C13; 
C6H2C14;  C6HC15;  C6C16,  being  known. 

It  is  necessary  to  distinguish  clearly  between  these  two 
classes  of  derivatives.  The  nomenclature  used  is  exemplified 
above.  Additive  compounds  are  named  in  the  same 
manner  as  the  binary  compounds  of  inorganic  chemistry 
(compare  benzene  dichloride,  C6H6C12,  with  zinc  dichlo- 
ride,  ZnCl2).  Substitution  compounds  are  named  by  at- 


BENZENES.  Iig 

taching  to  the  fundamental  name  syllables  indicating 
the  nature  of  the  substituting  bodies  and  also  numerical 
syllables;  thus,  C6H4C12  is  dichlorbenzene . 

The  assumed  structure  of  the  molecule  of  benzene  is 
shown  in  the  following  diagrams  of  the  carbon  nucleus — 
the  carbon  atoms  represented  by  dots — and  arrangement 
of  valencies.  Several  diagrams  are  given,  showing  sug- 
gestions as  to  manner  and  disposition  of  the  latent  valen- 
cies. 


I- 


Kekule 


• 

i 

Armstrong 


Ladenburg's  prism 


Carbon  atoms  in  benzene  (various  suggestions) 


Ladenburg's  prism  modified 

Benzene  derivatives  obtained  by  substituting  the  hydro- 
gen by  equivalent  atoms  or  groups  are  numerous  and  show 
many  instances  of  isomerism.  These  are  best  explained 
by  tridimensional  (stereo-chemic)  formulas  but  such  a 


I2O  ORGANIC    CHEMISTRY. 

method  is  not  here  available  and  the  ordinary  structural 
formulas  must  suffice. 

The  following  compounds  illustrate  these  substitutions 
and  the  nomenclature  of  them : 

C6H5C1 chlorbenzene. 

C6H4C12 dichlorbenzene. 

C6H3(HO)3 trihydroxybenzene. 

C6H4(COOH)(HO) carboxyhydroxybenzene. 

For  convenience  in  naming  compounds,  C6H5,  is  fre- 
quently called  phenyl,  and  C6H4,  phenylene. 

The  term  "hydroxy  "  in  these  names  is  often  abbreviated 
to  "oxy."  Thus,  C6H5HO  is  called  oxybenzene.  The 
conditions  of  symmetry  in  benzene  are  such  that  no  isomer- 
ism  is  to  be  expected  (and  none  has  been  observed)  in 
the  compounds  formed  by  a  single  substitution  of  the 
hydrogen.  Hence,  phenol,  hydroxybenzene,  is  identical 
in  nature  no  matter  how  prepared.  When  two  or  more 
hydrogen  atoms  are  replaced,  isomerism  at  once  becomes 
possible,  and  instances  become  very  numerous  when 
several  different  substituting  molecules  are  introduced. 
To  aid  in  expressing  the  formulas  of  these  isomeric  bodies, 
and  also  in  distinguishing  them  by  name,  the  normal 
benzene-molecule  is  represented  by  a  hexagon  which, 
when  unmodified,  stands  for  C6H6;  it  is  termed  a  "ring- 
symbol."  A  symbol  or  formula  at  any  angle  of  this 
hexagon  indicates  that  an  atom  of  hydrogen  is  replaced  by 
the  body  represented  by  that  symbol  or  formula.  The 
annexed  diagrams  will  show  the  detailed  structural  for- 
mula and  ring-symbol.  The  carbon  atoms  are  here  again 
represented  by  dots.  X  represents  any  monad  elements 
or  radicle. 


BENZENES.  121 


X 

I 


•-H 


I 
H 

Substitution  compound  and  ring  symbol 


The  position  of  the  substituting  body  is  immaterial  in 
this  case,  but  it  is  usually  placed  at  the  upper  angle. 
When  two  hydrogen  atoms  are  replaced  three  isomeric 
bodies  will  be  formed,  whether  the  replacement  is  by  the 
same  or  different  bodies.  To  assist  in  indicating,  the  angles 
are  distinguished  by  numbers  in  the  order  of  those  on  a 
clock,  thus: 


4 

Substitution  of  two  hydrogen-atoms  are  shown  in  the 
annexed  ring-symbols. 

XXX 


122  ORGANIC    CHEMISTRY. 

X,  as  before,  represents  any  monad  element  or  radicle. 
It  will  be  seen  that  1-5  and  1-6  are  identical,  respectively, 
with  1-3  and  1-2,  so  that  three  and  only  three  isomeric 
forms  are  to  be  expected.  This  accords  with  all  known 
facts.  Moreover,  the  rule  applies  to  cases  in  which  two 
different  substituting  molecules  appear.  The  numerical 
nomenclature  is  not  generally  used  in  these  instances, 
the  compounds  being  designated  by  prefixing  the  following 
syllables : 

ortho  for   1-2 

meta   for  1-3 

para    for  1-4 

Substitutions  of  three  hydrogen  atoms  by  three  atoms 
or  molecules  of  the  same  kind  give  rise  to  three  isomeric 
forms  which  are  exemplified  in  the  annexed  formulas  of 
the  three  trichlorbenzenes  together  with  distinctions  by 
the  two  systems  of  nomenclature  in  vogue. 


1-2-3  i-2-4  1-3-5 

Consecutive  Unsymmetric  Symmetric 

or  adjacent 


If  the  three  substituting  bodies  are  not  identical,  the 
isomerism  becomes  complex,  and  substitutions  of  four 
or  five  hydrogens  still  more  so,  but  substitution  of  six 
hydrogens  by  identical  bodies  gives  only  one  form.  The 
latter  point  is  exemplified  in  the  annexed  formula: 


BENZENES.  123 

COOH 

HOOC|/\COOH 
HOOcl      JcOOH 

COOH 

Mellitic  acid,  hexacarboxybenzene. 

No  uniform,  system  is  available  for  representing  additive 
compounds  by  ring-symbols.  A  provisional  method  is 
adopted  in  this  book  for  the  few  instances  in  which  such 
representation  is  required.  Additive  elements  or  groups 
are  indicated  by  placing  the  proper  sign  at  a  short  dis- 
tance from  the  angle  and  connected  by  a  bond.  There  is 
also  no  uniform  method  of  indicating  cyclic  combinations 
containing  less  than  six  carbon  atoms  nor  those  containing 
atoms  of  different  elements  (heterocyclic).  Some  chemists 
use  a  truncated  hexagon  for  five-membered  rings.  For 
indicating  the  heterocyclic  (pyridin)  ring,  C5H5N,  the 
benzene  hexagon  with  a  small  N  close  to  an  angle  will  be 
used  in  this  book.  Both  these  methods  are  exemplified  in 
the  formula  for  pyridin  hydride. 

For  illustration  and  comparison,  the  ring-symbols  of  a 
few  compounds  are  given  here.  The  substances  are 
described  in  the  following  pages. 


HO  N09  COOH 


Hydroxybeazene  Nitrobenzene  Carboxybenzene 

(Phenol)  (Benzoic  acid) 


124  ORGANIC    CHEMISTRY. 

HCO  CH2HO  HO 

0" 

Benzaldehyde  Benzyl  alcohol  Resorcinol 

(Bitter-almond  oil) 


COOH 


HCO 


HCO 


HO 


Salicylic  acid 


CH 


'HO 


OCH3 


)CH3 

Isovanillin 

NH, 


Picric  acid 


HS03 

Sulphanilic  acid 

1-4  Amidobenzene- 

sulphonic  acid 


HOMOLOGUES     AND     DERIVATIVES     OF     BENZENE. Ben- 

zene  is  the  first  member  of  a  series  of  the  general  formula 
CnH2n_6  of  which  the  following  compounds  are  examples: 


methylbenzene 
dimethylbenzene 
trimethylbenzene 
tetramethylbenzene 


Toluene  is  a  colorless  liquid,  of  sp.  gr.  0.870.  It  boils 
at  110°.  A  substitution  of  one  atom  of  the  benzene- 
hydrogen  of  toluene  must  produce  three  isomeric  forms, 


Benzene, 

C,H6 

Toluene, 

C7H8 

C6H5(CH3), 

Xylene, 

C8H10 

C6H4(CH3)2, 

Cumene, 

C9H12 

C6H3(CH3)3, 

Cymene, 

Ci0H14 

C6H2(CH3)4, 

BENZENES.  125 

since  the  substituting  group  must  take  a  position  either 
j-2  (ortho),  1-3  (meta),  or  1-4  (para),  with  reference  to  the 
methyl  group,  for,  as  the  structural  formula  and  syste- 
matic name  of  toluene  indicates,  it  is  not  a  seven-carbon 
chain  but  a  substitution  of  methyl  for  one  of  the  hydrogen 
atoms  of  benzene.  It  is  obvious,  however,  that  the  sub- 
stitution may  take  place  in  the  methyl  group.  This, 
which  is  termed  " side '-chain"  substitution,  gives  rise  to 
bodies  which  show,  in  empirical  formulas,  isomerisms  with 
the  ordinary  benzene  substitutions.  This  phenomenon  of 
side-chain  substitution  is  now  receiving  special  attention 


CH 


Methyl-benzene 
(Toluene) 

in  pathological  chemistry,  and  in  connection  with  theories 
of  immunity,  but  the  subject  is  still  imperfectly  developed 
and  is  too  complex  for  more  than  mention  here. 

H ydroxytoluene ,  C6H4(HO)(CH3),  of  which  there  are  three 
forms  is  isomeric  but  not  identical  with  C6H5CH2HO.  The 
latter  might  be  called  hydroxymethylbenzene  for  dis- 
tinction. It  is,  however,  known  as  benzyl  alcohol  and  is 
considered  to  be  the  true  alcohol  of  this  formula. 

Nitrobenzene,  C6H5NO2. — This  is  easily  prepared  by  the 
action  of  strong  nitric  acid  on  benzene.  It  is  a  colorless 
liquid,  with  an  odor  somewhat  like  that  of  essential  oil 
of  bitter  almonds,  for  which  it  has  been  used  as  a  sub- 
stitute in  flavoring  soaps  and  cosmetics.  It  is  known 


126  ORGANIC    CHEMISTRY. 

commercially    as    oil   of   myrbane.     The    reaction    for   its 
production  is: 

C6H6   +    HNO3    ==   C6H5NO2   +   H2O 

Aniline,  Phenylamine,  Amidobenzene ,  C6H5NH2. — This 
is  made  by  the  action  of  nascent  hydrogen  on  nitroben- 
zene, e.  g.,  by  mixing  nitrobenzene  with  tin  and  hydro- 
chloric acid  or  with  iron  filings  and  acetic  acid.  The  re- 
action is : 

C6H5N02    +   H6    ==   C6H5NH2   +    2H2O 

Aniline  is  a  liquid,  boiling  at  182°.  It  is  an  active 
poison.  By  the  action  of  oxidising  agents  it  becomes 
converted  into  bodies  of  complicated  composition,  some 
of  them  having  coloring  powers  of  great  beauty  and 
variety,  so-called  "aniline  or  coal-tar  colors."  Crude 
aniline,  commonly  known  as  "aniline  oil,"  contains  homol- 
ogous substances,  such  as  toluidines  (methyl  anilines)  and 
xylidines  (dimethyl  anilines). 

Phenol,  Hydroxybenzene ,  C6H5HO,  Carbolic  acid,  Phenic 
acid,  Phenylic  acid. — This  exists  in  coal-tar,  and  can 
be  made  artificially  by  several  processes.  It  forms  color- 
less crystals,  deliquescent,  and  soluble  in  water,  melting 
at  34°  and  boiling  at  187°.  It  has  an  odor  like  that  of 
kreasote.  It  is  sometimes  called  "coal-tar  kreasote." 
The  commercial  article  usually  has  a  pink  tinge.  Applied 
to  mucous  membranes,  phenol  promptly  produces  blanch- 
ing and  then  an  eschar.  Strong  alcohol  is  antidotal  in 
action.  The  hydrogen  in  the  hydroxyl  of  phenol  can 
easily  be  replaced  by  positives  yielding  a  series  of  com- 
pounds termed  "phenates"  or  "phenylates."  The  sodium 
compound  being  readily  soluble  in  water  and  less  corrosive 
than  phenol,  is  used  as  an  antiseptic  and  as  a  wash  for 
removing  skin-parasites  from  domestic  animals. 


BENZENES.  127 

Benzaldekyde,  C6H5HCO,  is  oil  of  bitter  almonds.  Its 
formation  from  amygdalin  by  a  species  of  fermentation 
is  pointed  out  elsewhere.  It  is  a  colorless  liquid,  heavier 
than  water,  and,  as  usually  made,  has  the  smell  of  hy- 
drogen cyanide,  since  that  body  is  formed  from  amygdalin 
at  the  same  time  as  the  benzaldehyde.  Oil  of  bitter 
almonds  has  been  used  in  confectionery  as  a  flavor.  It  is 
sometimes  substituted  by  nitrobenzene. 

Benzole  acid,  carboxybenzene,  C6H5COOH,  occurs  in 
various  resins,  especially  in  benzoin,  and  can  be  made 
artificially  by  several  methods.  The  usual  method  is 
by  oxidation  of  toluene;  another  is  from  hippuric  acid. 
Benzoic  acid  is  a  white  crystalline  solid,  with  faint  odor 
and  disagreeable  taste.  It  dissolves  but  sftghtly  in  cold 
water,  but  more  so  in  hot  water  and  alcohol.  It  sublimes 
at  a  temperature  below  its  boiling  point.  It  is  an  antisep- 
tic. 

Sodium  benzoate  is  a  white  crystalline  solid  with  faint 
odor.  It  is  soluble  in  water;  the  solution  has  a  somewhat 
nauseous  taste.  It  has  marked  antizymotic  properties 
and  is  now  used  as  a  preservative  in  foods  liable  to  ferment. 

Benzyl  alcohol,  Phenyl  carbinol,  C6H5(CH2HO),  is  of  little 
practical  importance,  but  is  interesting  because  it  is  the 
true  alcohol  of  this  series.  It  is  isomeric  with  the  hydroxy- 
toluenes  (cresols)  but  entirely  of  a  different  nature  and 
quite  different  in  properties. 


Benzyl  alcohol 

Resorcinol,   Resorcin,   Metadihydroxybenzene,   C6H4(HO)2 


128  ORGANIC    CHEMISTRY. 

(for  structural  formula  see  p.  124).  This  can  be  obtained 
from  the  resins  of  galbanum  and  asafetida  and  also  synthet- 
ically from  several  benzene  derivatives.  It  is  a  colorless, 
crystalline  body  soluble  in  water,  alcohol  and  ether.  It 
is  antiseptic. 

Pyrogallol,  Pyro gallic  acid,  C6H3(HO)3,  1-2-3  trihydroxy- 
benzene,  was  originally  obtained,  as  its  name  indicates,  by 
heating  gallic  acid.  It  is  a  colorless,  crystalline  body, 
soluble  in  water.  It  absorbs  oxygen  from  the  air  and 
decomposes.  The  action  is  especially  rapid  in  alkaline 
solution  and  is  utilised  in  developing  photographic  nega- 
tives and  in  the  analysis  of  gaseous  mixtures  containing 
free  oxygen. 

HO 


Pyrogallol 

Phloroglucol,  Phloroglucin,  C6H3(HO)3.— The  molecule 
of  this  body  is  supposed  to  be  tautomeric.  The  annexed 
formulas  show  two  possible  forms.  One  form  is  1-3-5 
trihydroxybenzene,  the  other  form  is  triketohexamethene. 


HO 

Hol    JHO 


Originally  obtained  from  a  glucoside,  phloridzin,  of  certain 
root -barks,  it  is  now  made  from  resorcinol.     It  is  a  color- 


BENZENES.  I2Q 

less,  crystalline  body,  soluble  in  water  and  alcohol.  The 
alcoholic  solution  is  used  in  mixture  with  a  solution  of 
vanillin  for  detection  of  hydrochloric  acid  in  gastric  juice. 
A  solution  of  phloroglucol  and  dilute  hydrochloric  acid  is 
used  for  detecting  some  forms  of  woody  tissue.  When 
the  solution  is  added  to  materials  containing  these  tissues, 
a  bright  red  stain  is  produced.  This  reaction  depends 
upon  the  existence  of  substances  somewhat  similar  to 
vanillin.  A  solution  of  phloroglucol  in  dilute  sodium 
hydroxide  is  used  as  a  test  for  formaldehyde. 

Phenolsulphonic  acids,  C6H4(HO)(HSO3).— Three  of  these 
are  possible;  all  are  known,  but  only  1-2  and  1-4  can  be 
obtained  by  the  direct  action  of  phenol  upon  sulphuric  acid. 
The  first  form  tends  to  pass  into  the  1-4  form,  slowly  when 
cold,  rapidly  when  hot.  These  acids  are  capable  of  form- 
ing salts  which  are  strongly  antiseptic  and  have  been  used 
as  disinfectants. 

Phenylsulphuric  acid,  Phenyl  acid  sulphate,  C6H5HSO4, 
is  empirically  isomeric  with  the  phenolsulphonic  acids  but 
quite  different  in  structure.  Its  potassium  salt  occurs  in 
urine,  and  is  one  of  the  so-called  ethereal  sulphates  the 
formation  of  which  is  supposed  to  be  dependent  on  the 
putrefactive  processes  taking  place  in  the  intestinal  canal. 

The  structural  formulas  will  show  the  relations  of  the 
four  bodies. 

HO  HO 

HSO, 

HSO3 

Phenolsulphonic  acids  Phenylsulphuric  acid 

Thymol  (see  structural  formula  p.  124),  isopropylmeta- 


130  ORGANIC    CHEMISTRY. 

hydroxy toluene,  is  one  of  the  ingredients  of  oil  of  thyme, 
and  can  be  prepared  synthetically.  It  forms  colorless 
crystals  that  melt  at  50°.  It  has  an  odor  recalling 
that  of  the  oil  of  thyme.  An  isomeric  form  is  known 
called  carvacroL  Thymol  has  marked  antiseptic  powers. 
Its  odor  prevents  its  use  as  a  food-preservative.  Its 
principal  medical  use  is  as  a  vermifuge  in  the  treatment  of 
uncinariasis  >  a  disease  due  to  the  presence  of  minute 
worms  in  the  intestinal  canal. 

£mmzo?/,i-2hydroxymethoxybenzene,  C6H4(HO)(CH3O), 
is  a  mixed  ether  of  phenyl  and  methyl  with  rlcoholic 
hydroxyl  also  present.  It  is  the  important  constituent 
of  kreasote  from  beechwood  tar.  When  pure  it  is  a  white 
solid  with  but  slight  irritating  qualities.  Commercial 
guaiacol  is  a  liquid,  often  very  impure,  and  decidedly 
irritating  to  mucous  membranes.  By  treatment  with 
carbonyl  chloride,  COC12,  a  derivative  having  the  formula 
(C6H4OCH3)2C03  is  obtained.  It  has  been  used  as  a  thera- 
peutic agent  under  the  name  guaiacol  carbonate. 

Vanillin  methylprotocatechuic  aldehyde  see  p.  124)  is 
the  principal  flavoring  constituent  of  vanilla,  which  con- 
tains from  i  to  2  per  cent.  It  is  now  made  artificially 
from  eugenol.  It  forms  colorless,  needle-like  crystals, 
with  the  well-known  agreeable  odor.  It  is  freely  soluble 
in  alcohol,  but  not  very  soluble  in  water. 

Picric  acid,  C6H2(NO2)3HO,  is  the  trinitro phenol  in  which 
the  nitro-groups  are  arranged  symmetrically  with  regard 
to  each  other  and  to  the  hydroxyl.  The  other  forms 
are  but  little  known.  Picric  acid  is  obtained  by  the 
oxidation  of  indigo,  silk,  wool  and  leather,  and  syntheti- 
cally by  the  oxidation  of  phenol.  Phenolsulphonic  acids 
mixed  with  nitrates  produce  some  picric  acid,  but  several 
lower  nitrophenols  are  also  formed.  Picric  acid  may  be 


BENZENES.  131 

produced  by  the  direct  oxidation  of  phenol  with  nitric 
acid,  but  the  action  is  apt  to  be  violent.  Picric  acid  is  a 
deep  yellow  solid,  soluble  in  water.  It  dyes  silk  and  wool 
without  a  mordant.  It  coagulates  albumin.  It  is  very 
bitter,  a  property  to  which  the  name  refers.  With  care 
it  can  be  sublimed  without  decomposition,  but  under 
some  conditions  explodes  with  great  violence.  The  high 
explosive  called  "lyddite"  is  picric  acid.  As  the  formula 
shows,  it  is  not  a  carboxyl  acid,  but  the  nitro-groups  give 
the  hydrogen  of  the  hydroxyl  acid  function.  This  hydro- 
gen may  be  replaced  by  positives,  forming  salts,  most  of 
which  are  explosive. 

Salicylic  acid,  orthohydroxycarboxybenzene,  oxybenzoic 
acid,  C6H4(COOH)(HO)  (see  p.  124),  differs  in  formula 
from  benzoic  acid  by  an  additional  atom  of  oxygen,  hence 
the  name  oxybenzoic  acid.  It  is  usually  made  from  sodium 
salicylate  obtained  by  the  action  of  carbon  dioxide  on 
sodium  phenate. 

Sodium  phenate.  Sodium  salicylate. 

NaC6H5O    +   CO2    =   NaC7H563 

Salicylic  acid  forms  colorless  prismatic  crystals,  sparingly 
soluble  in  water.  The  solution  gives  a  deep  violet  color 
with  ferric  salts.  It  has  high  antiseptic  qualities  and  is 
much  used  as  a  preservative  in  foods  and  beverages. 
Its  methyl  ester  exists  in  the  volatile  oils  of  wintergreen, 
(Gaultheria  procumbens)  and  birch  (Betula  lento).  By 
saponifying  these,  the  natural  acid  can  be  obtained;  this 
is  preferable  for  therapeutic  use  on  account  of  its  freedom 
from  the  dangerous  by-products  occasionally  present  in 
the  acid  made  from  phenol.  Salicylic  acid  has  a  marked 
restraining  action  on  several  starch-converting  enzyms. 


132  ORGANIC    CHEMISTRY. 


Cresols,  C6H4(CH3)HO,  methyl  phenols,  cresylic  acids. 
These  have  the  same  relation  to  toluene,  C7H8,  that  phenol 
has  to  benzene.  Phenol  is  hydroxybenzene ;  cresol  is  hy- 
droxytoluene.  They  exist  in  coal-tar.  Three  isomeric  forms 
are  known.  They  are  often  present  in  commercial  phenol. 

Lysol,  now  much  used  as  a  surgical  antiseptic,  is  a  mix- 
ture of  the  cresols  saponifed  by  caustic  soda  and  thus 
rendered  soluble  in  water. 

Eugenol,  allyl  guaiacol,  C6H3(C3H5)(OCH3)(OH).  This 
forms  the  greater  portion  of  oil  of  cloves,  and  occurs  in 
other  essential  oils.  It  differs  from  vanillin  in  containing 
the  monad  allyl  radicle,  C3H5,  in  place  of  the  aldehyde 
group  HCO.  By  oxidation  allyl  may  be  converted  into 
HCO,  and  vanillin  obtained.  This  is  now  the  commercial 
source  of  synthetic  vanillin. 

Piperonal.  The  structural  formula  shows  this  to  be  an 
aldehyde-ether.  It  bears  some  relation  to  vanillin  and 
benzaldehyde.  It  is  a  liquid  of  pleasant  odor.  . 

HCO 


BENZENES.  133 

QUINONES. — The  substitution  of  oxygen  for  hydrogen  in 
the  proportion  of  O2  for  H2  in  closed-chain  compounds, 
gives  rise  to  a  series  of  bodies  termed  quinones.  Some  of 
them  are  analogous  in  structure  to  hydrogen  dioxide,  and 
like  it  are  active  oxidising  agents.  Two  series  have  been 
obtained,  representative  of  1-2  and  1-4  substitutions. 
The  latter  series  true,  or  paraquinones,  are  of  the  greater 
importance.  Some  of  them  are  probably  tautomeric, 
oscillating  between  a  peroxide  and  a  ke tonic  structure. 
In  the  latter  condition  they  have  reducing  power. 

The  structural  formulas  of  these  forms  is  illustrated 
by  benzoquinone  : 


Benzoquinone 

Peroxide  form  Ketonic  form 

C.H40S  C4H4(CO)2 

Quinone,  benzoquinone,  the  type  substance,  may  be  pre- 
pared in  many  ways.  The  usual  method  is  by  oxidising 
aniline  with  chromic  acid.  It  forms  yellow  crystals  which 
have  a  penetrating  disagreeable  odor  and  irritate  the 
skin. 

Phthalic  acids ,  dicarboxybenzenes,  C6H4(COOH)2. — These 
are  the  final  products  of  the  oxidation  of  side-chains  of 
benzene  derivatives  and  their  preparation  is,  therefore, 
valuable  as  a  means  of  ascertaining  the  position  of  these 
chains,  since  the  forms  of  acid  yielded  will  be  dependent 
on  the  position  of  molecules  oxidised.  There  are,  of 
course,  three  forms  of  these  acids:  1-2,  1-3,  1-4.  The 


134  ORGANIC    CHEMISTRY. 

methods  used  depend  upon  the  form  of  the  acid  desired. 
The  most  important  is: 

Phthalic  acid,  C6H4(COOH)1(COOH)2,  1-2  dicarboxyben- 
zene. — This  is  obtained  by  the  oxidation  of  naphthalene, 
by  which  the  extra  ring  is  broken  and  its  carbon  con- 
verted in  carboxyl.  It  is  a  colorless,  crystalline  body 
soluble  in  water.  It  is  prepared  in  large  quantity  for 
the  manufacture  of  commercial  synthetic  products.  Its 
preparation  from  naphthalene  is  the  first  step  in  the 
manufacture  of  artificial  indigo-blue. 

Saccharin,  Benzosulphinide ,  C7H5NSO3. — The  struc- 
tural formula  shows  the  nature  of  this  body.  It  is  an 
imido-derivative  of  benzosulphonic  acid.  It  is  a  white 
crystalline  solid  soluble  in  water;  the  solution  is  very 
sweet.  Saccharin  has  been  estimated  as  several  hundred 
times  as  sweet  as  cane  sugar.  It  has  marked  antiseptic 
powers,  and  is  much  used  as  a  substitute  for  sugar  and 
sometimes  as  a  preservative. 


Saccharin 

The  following  formulas  show  several  benzene  derivatives, 
some  of  which  do  not  need  special  description : 

HCO 


HO 
HO 

Phenazine  Protocatechuic  aldehyde 


BENZENES.  135 


Phenylether 


PHTHALEINS. — These  are  complex  derivatives  of  phthalic 
acid.  Some  of  them  have  acquired  much  importance 
on  account  of  their  value  as  dyes  and  indicators,  and  one  of 
them,  fluorescein,  on  account  of  its  optical  properties. 
The  general  nature  of  the  structural  formula  is  shown  by 
that  for  phenolphthalein  given  below.  The  phthaleins  must 
not  be  confounded  with  the  "'pktkalins','9  a  less  important 
group,  not  requiring  special  consideration  here. 

Phenol phthalein  is  a  light  yellow  powder  almost  in- 
soluble in  water  but  freely  soluble  in  alcohol.  The  solution 
is  nearly  colorless  when  neutral  or  acid,  but  becomes  bright 
red  when  alkaline.  It  is  much  used  as  an  indicator. 

HO 


OYO 


H( 

\ / 

O C 

II 
O 

Phenol  phthalein 

Resorcinolphthalein,  fluorescein,  is  a  reddish  powder 
which  dissolves  in  strong  alkaline  solutions  to  produce  a 
dark-red  solution,  but  when  highly  diluted  the  liquid 


136  ORGANIC    CHEMISTRY. 

shows  a  vivid  green  fluorescence.  The  coloring  power  of 
fluorescein  is  so  great  that  large  bodies  of  water  may  be 
made  distinctly  fluorescent  by  moderate  quantities  of  the 
material,  and  it  has  been  used  for  tracing  underground 
connections  between  streams  and  springs. 

EOSINS,  RHODAMINS. — These  classes  of  colors,  now 
well-known  on  account  of  their  use  in  coloring  foods, 
beverages  and  confections,  are  derivatives  of  the  phtha- 
leins.  The  cosins  are  bright  red  dyes;  most  of  them  are 
fluorescent.  Eosin  proper  is  tetrabromofluorescein,  and 
erythrosin,  tetraiodofluorescein.  The  rhodamins  are  the 
phthalein  derivatives  of  1-3  amidophenol;  they  are  also 
brilliant  dyes  of  different  shades  of  red  and  fluorescent. 

Indol,  C8H7N.  According  to  the  system  of  nomencla- 
ture now  generally  used,  this  body  should  be  termed 
"in din."  The  structural  formula  shows  it  to  be  a  union 
of  a  pyrrol  ring  with  a  benzene  ring.  It  is  of  considerable 
importance  because  of  its  occurrence  among  the  products 
of  putrefaction,  and  pancreatic  digestion  of  proteids, 
and  also  its  relation  to  the  principal  coloring  matter  of 
indigo. 

Skatol  is  a  methyl  substitution  of  indol.  It  occurs  with 
indol  and  is  a  characteristic  ingredient  of  the  contents  of 
the  intestinal  canal. 


=C—  CH3 


Indol  (Indin)  Skatol  (Skatin) 

(Methyl  indin) 

Indigotin,    C16H10N2O2,    the    principal    coloring    matter 
of  indigo,  is  a  duplicated  indol  with  substitution  of  two 


BENZENES  137 

oxygen  atoms  for  four  hydrogen  atoms.  It  exists  in  the 
indigo  plant  in  the  form  of  a  glucoside,  "indican,"  which 
is  hydrolysed  by  dilute  acids  or  by  enzyms.  The  change 
can  be  brought  about  by  exposing  the  macerated  plant- 
tissues  to  air.  Indigotin  is  insoluble  in  water.  It  is  of  a 
bright  blue  color,  and  in  masses  has  a  copper  lustre. 
Natural  indigotin  is  contaminated  with  other  coloring 
matters.  To  render  indigo  available  for  dyeing  it  is 
made  soluble,  either  by  converting  it  into  a  sulphonic  acid 
or  into  indigo-white,  a  compound  containing  two  ad- 
ditional hydrogen  atoms  obtained  by  fermentation  methods, 
The  sulphonic  acid  dyes  directly;  the  indigo-white  is 
soluble  and  impregnates  the  fibre  and  when  exposed  to 
the  air  reverts  to  indigotin  and  becomes  blue  and  in- 
soluble. 

The  synthesis  of  indigotin  has  been  accomplished  in 
several  ways:  The  following  method,  now  employed  on  a 
practical  scale,  illustrates  the  general  methods  of  organic 
synthesis. 

Naphthalene  from  coal-tar  is  converted  into  phthalic 
acid,  C6H4(COOH)2  this  phthalimide,  C6H4(CO)2NH, 
this  into  anthranilic  acid,  C6H4(COOH)(NH2),  this  into 
a  body  of  the  formula  C6H4(COOH)(NH)(CH)(COOH), 
which  is  then  converted  into  indoxylcarboxylic  acid, 
C6H4(CO)(NH)(CHCOOH),  from  which  indigotin  is  ob- 
tained. 

Experiment  40. — Make  an  intimate  mixture  of  benzoic  acid  with 
twice  its  weight  of  quicklime,  and  heat  the  mixture  strongly  in 
an  apparatus  provided  with  a  condenser.  If  it  be  desired  to  ob- 
tain considerable  benzene  a  hard  glass  flask  and  condensing  appa- 
ratus must  be  used,  and  the  distillate  must  be  purified  by  shaking 
with  sodium  hydroxide  and  then  with  calcium  chloride  and  re- 
distilling. For  the  purpose  of  illustrating  this  method  of  obtaining 
pure  benzene,  a  distillation  of  10  grams  of  benzoic  acid  with  20 


138  ORGANIC    CHEMISTRY. 

grams  of  quicklime  will  be  sufficient.  A  testtube  with  bent 
delivery  tube  will  serve.  The  residue  in  the  retort  is  principally 
calcium  carbonate.  After  cooling,  it  may  be  treated  with  boiling 
water,  filtered,  and  the  material  collected  on  the  filter  and  tested 
with  hydrochloric  acid.  The  presence  of  a  carbonate  will  be 
shown  by  effervescence. 

Experiment  41. — Add  4  c.c.  of  sulphuric  acid  slowly  to  5  c.c. 
of  nitric  acid,  stirring  during  the  addition.  Allow  the  mixture  to 
cool,  place  the  vessel  containing  it  in  cold  water  and  add,  with 
stirring,  i  c.c.  of  benzene  in  small  portions,  stirring  between  each 
addition.  Allow  the  mixture  to  stand  until  the  action  is  complete; 
add  considerable  water,  stir  and  allow  to  stand  for  a  time.  Nitro- 
benzene settles  as  in  an  emulsion  with  water.  It  should  be  washed 
several  times  by  shaking  it  with  water  and  allowing  the  mixture  to 
settle.  The  characteristic  odor  will  be  noticed.  Note  also  that 
the  product  floats  in  the  mixture  of  acids  but  sinks  in  water. 
The  experiment  may  be  conveniently  performed  in  a  testtube 
with  foot,  as  heat  is  not  required. 

Experiment  42. — Mix  about  equal  volumes  (i  c.c.  of  each)  of 
nitrobenzene,  water  and  hydrochloric  acid,  and  a  little  granulated 
tin,  or  fine  tinfoil,  cut  into  very  small  pieces.  Care  should  be 
taken  not  to  use  common  foil  as  this  is  largely  lead.  It  may  be 
necessary  to  warm  the  mixture  slightly  to  maintain  the  evolution 
of  hydrogen.  The  nitrobenzene  will  be  converted  into  aniline. 
To  detect  the  latter,  slightly  dilute  the  mixture  and  add  a  fresh 
solution  of  bleaching  powder  or  solution  of  chlorinated  soda.  A 
transient  bluish-violet  tint  will  appear. 

Experiment  43. — Add  a  few  drops  of  a  dilute  solution  of  ferric 
chloride  to  a  small  amount  of  salicylic  acid  in  a  watch  glass  or 
porcelain  basin.  A  violet  solution  is  produced. 

Experiment  44. — Mix  about  o.i  gram  of  salicylic  acid  with  20 
c.c.  of  water,  to  which  a  few  drops  of  sodium  hydroxide  have  been 
added,  and  shake  the  liquid  until  the  acid  has  been  dissolved.  If 
the  solution  does  not  occur  in  a  few  minutes  add  more  sodium 
hydroxide.  The  solution  will  contain  sodium  salicylate.  Add 
enough  sulphuric  acid  to  render  the  liquid  slightly  acid,  then  add  10 
c.c.  of  ether  and  shake  well.  Allow  the  mixture  to  stand  until 
some  ether  separates,  pour  this  off,  evaporate  it  and  test  the 
residue  for  salicylic  acid  as  noted  above.  This  is  an  extraction 
with  an  "immiscible  solvent." 


BENZENES.  139 

Experiment  45. — Test  a  small  amount  of  benzoic  acid  by  the 
method  given  in  Experiment  43.  A  brown  precipitate  will  be 
formed. 

Experiment  46. — Prepare  sodium  benzoate  and  extract  benzoic 
acid  from  it  by  the  method  of  Experiment  44,  substituting  benzoic 
acid  for  salicylic.  Test  the  benzoic  acid  by  odor  and  reaction  with 
iron. 

Experiment  47. — Mix  a  very  little  aniline  with  a  drop  of  chloro- 
form, add  a  few  drops  of  a  strong  solution  of  sodium  hydroxide  in 
alcohol,  and  heat  the  mass  gently  by  immersing  it  in  warm  water. 
A  peculiar  and  very  disagreeable  odor  will  be  developed,  due  to 
a  body  called  phenylcarbamine  or  isonitrile,  C6H5NC. 

Experiment  48. — Mix  i  gram  of  phenol  with  6  c.c.  of  strong 
sulphuric  acid  and  i  c.c.  of  water;  stir  and  heat  for  a  short  time 
by  immersing  the  testtube  in  boiling  water;  1—2  and  1—4  phenol- 
sulphonic  acids  are  formed.  The  1—3  form  cannot  be  obtained 
by  this  method. 

Experiment  49. — Liquefy  phenol  by  adding  a  few  drops  of 
water  to  a  gram  of  the  crystals;  add  some  of  this  liquid  to  some 
white  of  egg.  The  albumin  is  coagulated.  This  is  a  distinction 
between  phenol  and  true  kreasote,  as  the  latter  does  not  coagulate 
albumin. 

Experiment  50. — Place  about  20  c.c.  of  bromine  water  in  a 
beaker  and  stir  it  with  a  glass  rod  carrying  a  small  drop  of  liquid 
phenol.  A  yellowish- white  precipitate  of  tribromphenol  is  produced. 

Experiment  51. — Dissolve  about  o.i  gram 'of  potassium  nitrate 
in  a  few  drops  of  water;  evaporate  the  solution  to  dryness  in  a 
watch  glass  over  the  steam  bath  and  add  to  the  residue  a  few  drops 
of  the  phenolsulphonic  acids  obtained  in  Experiment  48  and  smear 
the  liquid  over  the  glass  with  a  glass  rod.  It  will  assume  a  yellow 
tint  owing  to  the  formation  of  nitrophenols,  including  picric  acid. 
Add  more  water  and  pour  the  liquid  into  a  small  beaker,  dilute 
further  with  water  and  then  neutralise  with  ammonium  hydroxide 
or  sodium  hydroxide.  A  deep  yellow  color  is  developed  owing  to 
the  formation  of  a  picrate. 

If  the  mixture  of  phenol  and  sulphuric  acid  be  heated  for  several 
hours  in  boiling  water,  it  is  mostly  changed  into  a  phenoldisul- 
phonic  acid,  and  the  yield  of  picric  acid  from  this  is  much  greater 
than  that  obtained  in  the  above  experiment. 

Experiment  52. — Dissolve  a  little  saccharin  in  water,  acidulate 


140  ORGANIC    CHEMISTRY. 

slightly  with  sulphuric  acid  and  proceed  as  in  Experiment  44. 
The  saccharin  will  be  left  as  a  crystalline  residue,  the  nature  of 
which  is  easily  recognised  by  its  taste. 

Naphthalene,  C10H8,  often  called  coal-tar  camphor,  is 
obtained  from  coal-tar,  in  the  form  of  white,  somewhat 
fragrant,  crystalline  scales.  It  melts  at  80°.  It  is 
slightly  soluble  in  boiling  water.  It  is  used  extensively 
to  protect  goods  against  moths.  Naphthalene  consists  of 
a  double  ring  of  carbon  atoms  saturated  with  hydrogen; 
thus  : 

H       H 


H—  C       C      C—  H 

I!      I      II 

H—  C      C      C—  H 


C       C 

A  A 

This  formula  is  usually  expressed  by 


The  naphthalene-ring  may  be  oriented  in  the  same 
manner  as  the  benzene-ring,  beginning  at  the  upper  right 
hand  angle  and  numbering  in  the  direction  of  the  num- 
bers on  a  clock. 


A  substitution  of  one  atom  of  hydrogen  in  naphthalene 
may  produce  two  isomeric  derivatives,  depending  on  the 
position  of  the  substituting  body.  Substitution  at  points 


BENZENES.  141 

i,  4,  5  or  8  are  termed  " alpha"  derivatives;  substitutions 
at  2,  3,  6  or  7  are  termed  ''beta"  derivatives.  Each 
may  be  more  definitely  indicated  as  shown  in  one  of  the 
ring-symbols. 

Naphthols,  hydroxy  naphthalenes ,  C10H7HO. — When  naph- 
thalene is  dissolved,  in  strong  sulphuric  acid,  a  mixture  of 
alpha-  and  betanaphthalenesulphonic  acids  is  obtained. 
If  these  be  separated  and  saponified  with  sodium  hy- 
droxide, each  will  yield  the  corresponding  hydroxide 
(naphthol).  The  two  naphthols  are  much  alike,  being 
white,  crystalline  bodies,  freely  soluble  in  alcohol,  spar- 
ingly in  water  and  possessing  marked  antiseptic  and 
germicide  powers.  Betanaphthol  is  almost  exclusively  used. 

Betanaphthol,  (naphthol),  is  a  colorless  crystalline  powder, 
soluble  in  about  1000  parts  of  cold  water,  75  parts  of 
boiling  water,  very  soluble  in  alcohol,  ether,  chloroform  and 
alkaline  solutions.  It  becomes  slightly  yellow  on  expo- 
sure to  light.  It  is  used  as  an  antiseptic  and  preservative. 

The  naphthols  yield  sulphonic  acids  and  nitro-deriva- 
tives  exhibiting  numerous  instances  of  isomerism.  A  few 
of  these  are  of  considerable  practical  importance. 

Dinitro-alphanaphthols . — One  form  is  known  as  Mar- 
tins' yellow  and  naphthol  yellow.  It  is  a  bright  yellow 
powder  of  high  coloring  power  and  has  been  used  as  a 
color  for  food  and  confections,  but  the  fact  that  in  large 
doses  it  produces  functional  disturbances,  has  led  to  the 
prohibition  of  this  use. 

Naphthol  yellow  5,  a  sulphonated  derivative  of  naph- 
thol yellow,  is  a  yellow  powder  of  high  coloring  power,  and 
being  apparently  much  less  active  than  the  latter  has 
displaced  it  as  a  food  color. 

Abrastol,  Asaprol. — These  are  trade  names  of  a  calcium 
betanaphtholsulphonate,  used  as  a  food  preservative. 


I42  ORGANIC    CHEMISTRY. 

The    following    structural    formulas  show  several  naph- 
thalene  derivatives. 


HO  HO 


a-naphthol  /?-naphthol  a-/3-naphthol 

a-hydroxynaphthalene       /3-hydroxynaphthalene 


NH2 


a-amido-naphthalene 

Anthracene,  C14H10  (for  structural  formula  see  p.  135). — 
This  is  present  in  in  the  higher -boiling  portions  of  coal- 
tar.  It  crystallises  in  colorless  scales  that  show  violet  fluor- 
escence. It  melts  at  213°  and  distils  at  about  360°.  It  is 
insoluble  in  water  and  only  slightly  in  cold  alcohol,  benzene 
and  carbon  disulphide.  An  important  use  of  anthracene 
is  for  the  synthetic  production  of  alizarin,  the  coloring 
matter  of  madder-root.  The  first  step  in  this  synthesis 
is  the  treatment  of  anthracene  with  chromic  acid,  by  which 
anthroquinone,  C14H8O2,  is  formed.  Anthroquinone  is 
converted  by  means  of  strong  sulphuric  acid  into  a  mono- 
sulphonate,  and  this,  treated  with  sodium  hydroxide  and 
potassium  chlorate,  yields  alizarin.  This  method  of  pro- 
duction has  proved  so  satisfactory  that  the  cultivation  of 
madder  (Rubia  tinctoria)  has  been  discontinued. 

Anthraquinone,  C14H8O2,  is  a  diphenyldiketone  (see  under 
Quinones,  p.  133),  obtained  by  the  oxidation  of  anthra- 
cene with  chromic  acid.  It  forms  yellow  crystals.  It  is 


BENZENES.  143 

not  an  oxidising  agent,  and,  unlike  some  other  quinones, 
is  not  reduced  by  sulphurous  acid.  Its  production  from 
anthracene  is  a  standard  method  of  assaying  the  crude 
forms  of  the  latter  substance. 

Experiment  53. — Dissolve  i  gram  of  commercial  anthracene 
in  45  c.c.  of  glacial  acetic  acid;  filter  if  necessary,  bring  to  boiling 
and  add  a  solution  of  chromic  acid  in  acetic  acid  by  small  por- 
tions. The  chromic  acid  solution  is  made  by  dissolving  10  grams 
of  chromic  anhydride  in  10  c.c.  of  50  per  cent,  acetic  acid.  This 
solution  should  be  added  until  the  boiling  mixture  produces  a 
red  stain  on  a  piece  of  silver  which  shows  that  the  chromic  acid 
is  no  longer  reduced.  Allow  the  mass  to  cool,  dilute  with  150 
c.c.  of  water,  allow  to  stand  a  few  hours,  collect  the  precipitate 
on  a  filter,  wash  with  water,  then  with  solution  of  sodium  hydrox- 
ide and  again  with  water. 

Benzidin,  diamidodiphenyl,  (C6H4)2(NH2)2,  belongs  to  the 
class  of  polynucleated  cyclic  compounds  that  is  constituted 
of  independent  rings  joined  directly  at  one  point,  as  con- 
trasted with  duplicated  rings,  such  as  naphthalene  and 
phenanthrene,  or  conjugated  rings  such  as  phenyl  ether, 
phenazin,  anthracene  and  alizarin. 

Benzidin  has  lately  been  brought  into  notice  as  appli- 
cable to  the  volumetric  determination  of  sulphuric  acid 
and  sulphates  on  account  of  the  insolubility  of  benzidin 
sulphate.  A  solution  of  benzidin  hydrochloride  is  used  in 
this  process.  Many  of  its  derivatives  are  valuable  dyes. 

NH2 


144  ORGANIC    CHEMISTRY. 

Diphenyl,  C6H5C6H5,  is  another  compound  of  the  same 
class  as  benzidin. 

Carbazol  1-2  imido-diphenyl ,  (C6H4)2NH. — This  exists 
in  crude  anthracene  as  a  potassium  derivative.  It  is 
employed  in  the  preparation  of  synthetic  colors  and  as 
a  test  for  nitrates. 

COAL-TAR  COLORS. 

The  coal-tar  colors  are  a  very  numerous  group  of  com- 
pounds obtainable  from  the  hydrocarbons  present  in  the 
tar.  They  are  all  closed-chain  derivatives,  but  not  all 
from  benzene.  The  first  color  discovered  was  a  violet 
which  Perkin  obtained,  in  1856,  while  experimenting  with 
aniline.  Hofmann  (1859)  produced  a  brilliant  red  color 
magenta,  from  aniline,  and  the  following  year  the  manufac- 
ture of  it  was  begun.  From  that  date  the  number  rapidly 
increased  and  they  began  to  displace  the  natural  colors. 
In  1868  alizarin,  the  coloring  matter  of  madder,  was 
obtained  by  synthesis  from  anthracene  and  recently 
indigo  has  been  made  from  naphthalene. 

On  account  of  the  almost  exclusive  use  of  crude  aniline 
in  the  manufacture  of  these  colors  in  the  early  period, 
they  were  termed  "aniline  colors"  a  name  which  is  still 
largely  used,  although  some  of  the  most  used  are  not 
made  from  aniline  or  its  immediate  derivatives. 

As  a  class  these  bodies  are  brilliant  in  tint,  of  high 
coloring  power  and  soluble  in  water  and  alcohol.  They 
include  every  known  shade  and  have  to  a  great  extent 
replaced  the  natural  dyes.  They  are  much  used  for 
coloring  foods,  beverages  and  household  articles,  and 
their  sanitary  relations  have  been  the  subject  of  much 
investigation  and  discussion. 

Their  composition  is,   as  a  rule,  very  complex,  but  as 


COAL-TAR    COLORS.  145 

nearly  all  of  them  are  produced  from  simple  substances 
(e.  g.,  benzene,  naphthalene,  anthracene)  by  synthetic 
methods,  the  structural  formulas  are  mostly  known  with 
certainty.  The  commercial  colors  include  representatives 
of  all  the  larger  groups  of  closed-chain  derivatives.  The 
important  ones  are  considered  in  connection  with  the 
groups  to  which  they  belong.  The  following  list  will 
indicate  the  variety  of  types  they  represent.  A  few 
colors  not  classified  elsewhere  are  here  described: 

Nitro-  and  Nitroso -colors. — Picric  acid,  naphthol  yellow, 
naphthol  yellow  S,  naphthol  green. 

Azo -colors. — Methyl  orange,  Bismarck  brown,  Congo  red. 

Ketonic  Colors. — Alizarin,  chrysophanic  acid. 

Phenylme thane  Derivatives. — Auramin,  magenta  (fuch- 
sin),  malachite  green,  phenolphthalein,  fluorescein,  eosins, 
rhodamines,  methyl  violet. 

Sulphur  Derivatives. — Methylene  blue. 

As  the  systematic  names  of  these  bodies  are  generally 
long  and  awkward,  they  are  almost  always  known  by 
commercial  titles  which  are  arbitrary  and  often  fanciful. 
Abbreviations  are  used  to  indicate  shade,  special  con- 
dition or  manufacturer.  A  few  of  these  abbreviations 
are  here  noted: 

Letters  such  as  J,  JJ,  B,  BB,  OOOO,  are  descriptive 
of  the  shades.  Eosin  J  indicates  an  eosin  with  a  yellow 
shade  (Fr.  jaune)\  German  chemists  often  use  G  for  this. 
JJ  means  a  stronger  yellow  shade;  OOOO  a  strong  orange 
shade.  S  generally  means  sulphonation ;  naphthol  yellow 
S  is  the  sulphonated  derivative  of  naphthol  yellow.  BASF 
(Badische  Anilin  und  Soda  Fabrik)  is  an  example  of  a 
manufacturer's  name. 

A  few  of  these  colors  are  insoluble  in  water.  Some 
azo-colors  insoluble  in  water  are  soluble  in  oils,  to  which 


146  ORGANIC    CHEMISTRY. 

they  impart  an  orange  or  yellow  tint.  They  are  now 
often  used  in  coloring  fatty  foods,  especially  butter  and 
cheese.  Many  colors  are  affected  by  acid  or  alkaline  so- 
lutions and  are  used  as  indicators. 

Ros aniline. — This  is  produced  whenever  crude  aniline, 
which  always  contains  toluidines  (methylanilines),  is 
treated  with  oxidising  agents.  Arsenic  acid,  nitroben- 
zene and  mercuric  nitrate  are  the  oxidising  agents  practi- 
cally used.  The  arsenic  acid  method  was  the  first  and 
hence  all  the  rosaniline  products  were  liable  to  contain 
arsenic.  Rosaniline  is  generally  formulated  as  a  deriva- 
tive from  methane  by  substitution  of  all  its  hydrogen 
by  monad  groups. 

C6H4(CH3)(NH2) 

C6H4(NH2) 

C6H4(NH2) 

OH 

Rosaniline  forms  salts  with  acids  some  of  which  are 
important  dyes.  One  of  these  is:  magenta,  fuchsin, 
aniline  red,  rosaniline  hydrochloride.  It  is  soluble  in  water 
producing  a  brilliant  red  solution  of  high  coloring  power. 
It  is  used  largely  for  coloring  foods  and  beverages.  The 
name  "magenta"  is  an  interesting  instance  of  the  fanciful 
source  of  these  color-names.  It  refers  to  the  battle  at 
Magenta,  Italy,  fought  in  the  year  in  which  the  color  was 
first  prepared. 

Methylene  blue,  C16H18N3SC1.— This  is  a  complicated 
sulphur  derivative,  which  has  been  used  as  a  therapeutic 
agent  and  also  for  staining  pathologic  and  bacteriologic 
preparations. 

Methyl  violet,  C24H28N3C1,  is  a  product  of  oxidation  of 
dimethylaniline.  It  is  of  very  high  coloring  power  and  is 
also  an  antiseptic.  It  is  used  in  treatment  of  ulcers  and 
wounds  under  the  trade  name  "pyoktanin  blue." 


TERPENES.  147 

TERPENES. 

The  ter penes  are  cyclic  hydrocarbons  having  the  general 
formula  (C5H8)n.  When  oxidised  they  form  camphors  and 
resins.  The  terpenes  may  be  considered  as  cyclic  com- 
pounds in  which  one  or  more  latent  valencies  exist. 

The  formulas  on  page  148  are  suppositions,  and  only 
suggestive,  but  indicate  the  complexity  of  the  structure  of 
these  compounds. 

Many  essential  oils  consist  almost  entirely  of  terpenes, 
others  of  a  mixture  of  terpenes  with  oxygenated  bodies. 
The  terpenes  are  capable  of  polymerisation,  and  often  show 
optical  activity.  The  natural  forms  are  sometimes  com- 
posed of  equivalent  proportions  of  dextro-  and  levorota- 
tory  modifications. 

The  following  classification  of  the  terpenes  is  based  upon 
the  differences  in  their  molecular  weights : 

1.  Hemiterpenes,     C5H8 

2.  Terpenes,  C10H16 

3.  Sesquiterpenes,  C15H24 

4.  Diterpenes,          C2oH32 

5.  Poly  terpenes,      n(C10H16) 

Pinene,  C10H16,  constitutes  the  principal  portion  of  oil 
of  turpentine.  It  is  a  colorless  liquid  possessing  an  aro- 
matic odor.  It  unites  with  hydrochloric  acid  to  form 
pinene  hydrochloride,  C10H17C1,  which,  from  its  resemblance 
in  physical  properties  to  camphor,  has  been  called  "arti- 
ficial camphor."  When  oil  of  turpentine  is  mixed  with 
alcohol  and  nitric  acid  and  allowed  to  stand  for  several 
days,  a  crystalline  compound  separates  which  has  the 
composition  C10H18(OH)2  +  H2O,  and  is  known  as  terpin 
hydrate.  This  compound  forms  colorless  tabular  crystals 
possessing  a  slightly  aromatic  odor  and  a  bitter  taste,  and 
is  used  in  medicine  as  an  expectorant. 


1 48 


ORGANIC    CHEMISTRY. 


H 
H— C— H 

i 

HC  CH 


H  H 

H— C— H  H— C— H 


/ 
H,C 


HC  CH2  HoC 


V 

CH 


\ 
CH 

II 
CH 

\ 
H  9  H 


H,C     CH 


or         |  / 


HC 

V  \ 
H    CH 


\^>  1   A  T   T        V_x        T   T  A   A  \-s  A   A 

H3C— C— CHS     H-C-C-C-H    H-C— C— C~-H 

i  iii  iii 


H 

Pinene 


H 
H— C— H 


H  H  H  H    H    H 

Camphene 

H 

H— C— H 
H>C-C-C<H 


H,C 

\ 


CH. 


HAH 


C  H 

H— C=C— C— H 

i  A 


i-U-H 

H 
H 

H— C=C— C— H 

u 


Terpinene 
(Two  arrangements  of  the  suggested  formula.) 


CAMPHORS.  149 

Camphene,  C10H16,  is  a  white  crystalline  solid,  which  can 
be  oxidised  to  form  camphor. 

Limonene,  also  known  as  hesperidene,  carvene  and  citrene, 
constitutes  almost  the  entire  portion  of  several  of  the 
volatile  oils,  notably  oil  of  orange  peel.  Oil  of  lemon 
peel  consists  of  a  mixture  of  pinene  and  limonene.  Many 
of  the  volatile  oils  such  as  orange  and  lemon  consisting 
almost  entirely  of  terpenes,  lose  their  characteristic  odor 
upon  standing  and  acquire  the  odor  of  oil  of  turpentine, 
the  change  being  due  to  some  obscure  molecular  rear- 
rangement. This  change  is  usually  accompanied  by  a 
thickening  and  resinification  of  the  oil,  due  to  partial 
oxidation  of  the  terpenes. 

Dipentene,  Sylvestrene,  Terpinolene,  Ter pinene  and  Phel- 
landrene,  all  have  the  formula  C10H16  and  possess  similar 
properties  to  the  terpenes  already  described. 

Terebene  is  a  mixture  of  several  of  the  terpenes  (pinene, 
terpinene  and  dipentene)  and  is  produced  by  the  action 
of  sulphuric  acid  on  oil  of  turpentine. 

Members  of  the  classes  sesquiter penes,  C15H24,  and  diter- 
penes,  C20H32,  are  found  in  some  volatile  oils. 

Colophene,  C20H32,  is  a  diterpene,  which  is  formed  as  a 
by-product  in  the  manufacture  of  terebene. 

Polyterpenes  (C10H1-6)X,  exist  in  caoutchouc  and  gutta 
percha  and  may  be  formed  by  the  polymerisation  of  oil 
of  turpentine. 

CAMPHORS. 

The  camphors  are  oxygenated  derivatives  of  the  ter- 
penes. They  are  sometimes  called  stearoptenes  to  dis- 
tinguish them  from  the  eleoptenes  or  liquid  portions  of  the 
volatile  oils  in  which  they  usually  occur.  Some  of  them 


150  ORGANIC    CHEMISTRY. 

are  alcohols  while  others  resemble  the  ketones.  They 
are  completely  volatile  without  decomposition  and  may 
be  purified  by  sublimation. 

Ordinary  camphor,  C10H16O,  sometimes  called  Japan 
camphor,  is  obtained  by  distilling  the  wood  of  a  species 
of  cinnamon  (Cinnamomum  camphora)  in  a  current  of 
steam.  It  has  also  been  obtained  synthetically  from  oil  of 
turpentine  by  converting  the  pinene  into  camphene  which 
readily  yields  camphor  by  oxidation. 

Camphor  is  a  crystalline  solid,  possessing  a  character- 
istic odor  and  a  pungent,  afterward  a  cooling,  taste.  It  is 
sparingly  soluble  in  water  but  readily  soluble  in  alcohol, 
ether,  chloroform,  petroleum  spirit  and  fixed  and  volatile 
oils,  the  solution  of  the  natural  product  being  dextro- 
rotatory. It  can  be  ignited  readily  and  burns  with  a 
luminous,  smoky  flame.  With  bromine,  camphor  forms 
a  derivative  known  as  monobromated  camphor,  C10H15BrO, 
which  forms  colorless,  prismatic  crystals,  melting  at  76° 
with  a  slight  odor  and  a  pungent  camphoraceous  taste. 

Borneol  or  Borneo  camphor,  C10H18O,  is  obtained  in  a 
similar  manner  to  ordinary  camphor  from  the  wood  of 
Dryobalanops  aromatica.  It  may  be  obtained  from  or- 
dinary camphor  by  the  action  of  sodium. 

LiwaZ0oJ,C10H17OH;  GVramW,  C10H17OH;  CY/ra/,C10H16O, 
and  Citronellal,  C10H20O,  are  odorous  bodies  belonging  to 
this  class,  obtained  from  certain  volatile  oils,  citral  being 
present  in  oil  of  lemon. 

Menthol,  C10H20O,  is  the  stearoptene  obtained  from 
volatile  oils  of  several  varieties  of  peppermint.  Menthol 
forms  colorless,  needle-shaped  crystals  melting  at  46° 
having  a  warm  mint -like  taste,  followed  by  a  cooling  sen- 
sation when  air  is  inhaled  through  the  mouth. 


ESSENTIAL  OILS.  151 

ESSENTIAL  OILS. 

Essential  oils,  often  called  volatile  oils,  are  the  liquid 
proximate  constituents  to  which  the  characteristic  odors 
of  plants  are  due.  They  are  obtained  from  flowers,  seeds, 
leaves,  stems,  barks  and  roots,  mostly  by  distillation  with 
water,  the  volatile  oil  passing  over  with  the  steam  and 
condensing  with  it.  Some  of  the  aromatic  waters  used 
in  medicine,  such  as  rose  water  and  orange  flower  water, 
are  obtained  as  by-products  in  the  distillation  of  the 
essential  oils.  The  essential  oils  are  usually  mixtures  of 
terpenes  and  camphors  although  some  consist  of  esters, 
aldehydes  or  ketones. 

The  ESSENTIAL  OILS  are  distinguished  by  their  complete 
volatility,  comparative  insolubility  in  water  and  complete 
solubility  in  alcohol,  ether,  chloroform  and  similar  solvents. 
They  are  sometimes  obtained  by  expression,  as  with  oils 
of  orange  and  lemon,  and  may  be  extracted  from  the  plant 
tissues  by  the  use  of  appropriate  solvents.  They  may  be 
divided  into  four  classes,  viz.: 

Terpenes:  Oils  consisting  mainly  of  members  of  the 
class  of  terpenes,  as  oil  of  lemon. 

Oxygenated:  Oils  consisting  of  aldehydes,  esters  or 
ketones  often  associated  with  small  amounts  of  terpene, 
as  oil  of  cinnamon. 

Sulphurated:  Containing  sulphur,  as  oil  of  mustard. 

Nitrogenated :  Containing  nitrogen,  as  oil  of  bitter 
almond. 

It  will  be  impossible  to  give  more  than  a  brief  outline  of 
some  of  the  important  volatile  oils. 

Oil  of  turpentine  is  obtained  by  the  distillation  of  the 
natural  oleoresin  of  Pin  us  palustris:  it  consists  almost 
entirely  of  pinene. 


152  ORGANIC    CHEMISTRY. 

Oil  of  anise  is  principally  composed  of  anethol,  a  meth- 
oxy-derivative  of  benzene. 

Oil  of  black  mustard  is  allyl  isothiocyanate  associated 
with  a  small  amount  of  carbon  disulphide. 

Oil  of  cinnamon  is  principally  cinnamic  aldehyde. 

Oil  of  cloves  and  oil  of  pimenta  consist  mainly  of  eugenol 
(allylguaiacol). 

Oil  of  lavender  flowers  consists  almost  entirely  of  linalool 
and  geraniol. 

Oil  of  lemon  consists  of  pinene,  limonene  (a  dextro- 
rotatory terpene),  citral  and  a  small  amount  of  citronellal. 

Oil  of  orange  peel  consists  mainly  of  limonene  and 
geraniol. 

Oil  of  pennyroyal  contains  several  ketones,  the  principal 
one  being  pulegone. 

Oil  of  peppermint  is  very  complex  in  its  constitution. 
It  contains  pinene,  limonene,  aldehydes,  alcohols  and 
esters. 

Oil  of  rose  contains  geraniol  associated  with  a  hydro- 
carbon having  the  formula  C20H42. 

Oil  of  sassafras  contains  safrol,  eugenol,  pinene  and  a 
benzene  derivative. 

Oil  of  sweet  birch  and  oil  of  gaultheria  consist  of  methyl 
salicylate,  associated  with  a  small  amount  of  terpene. 

Oil  of  violets,  so  called,  is  a  product  obtained  from 
essential  oil  of  orris.  In  concentrated  form  it  bears  very 
little  resemblance  in  odor  to  violets,  but  when  largely 
diluted  with  alcohol  the  odor  is  similar. 


RESINS. 

The  resins  are  also  products  resulting  from  the  oxidation 
of  the  terpenes  and  are  associated  in  plant  tissues  with 


•RESINS.  153 

other  proximate  principles,  such  as  volatile  oils  and  gums. 
They  usually  exhibit  the  characters  of  acids  or  anhydrides 
and  are  decomposed  by  strong  heat.  They  are  divided 
into  three  groups:  i,  true  resins;  2,  oleoresins;  3,  gum- 
resins. 

The  hard  or  true  resins,  of  which  ordinary  resin  or 
colophony  (sometimes  called  rosin)  is  a  type,  are  fusible 
solids  capable  of  crystallisation  under  favorable  conditions, 
insoluble  in  water,  but  soluble  in  one  or  more  of  the  follow- 
ing solvents:  alcohol,  ether,  chloroform,  carbon  disul- 
phide,  acetone,  petroleum  spirit,  benzene  and  fixed  or 
volatile  oils.  They  often  combine  with  alkaline  hydroxides 
to  form  compounds  known  as  resin  soaps.  They  are  con- 
tained in  various  plant  tissues  and  are  often  obtained  as 
exudations  from  living  plants,  in  which  case  they  may 
be  pathological  products,  caused  by  wounding  the  tissues 
in  which  they  exist. 

Colophony  or  common  resin  is  obtained  as  a  residue 
when  the  oleoresin  of  the  pine  tree  is  distilled  for  obtaining 
oil  of  turpentine.  It  consists  largely  of  abietic  anhy- 
dride, C44H62O4,  which  is  converted  into  abietic  acid  by  the 
action  of  alcohol  and  water. 

Dammar,  Copal  and  Amber  are  fossil  resins  used  in  the 
manufacture  of  varnishes  and  lacquers. 

Lac  is  a  resinous  exudation  from  several  species  of 
oriental  trees,  occasioned  by  the  puncture  of  an  insect. 

Shellac  is  the  purified  product  occurring  in  thin,  trans- 
parent layers. 

Guaiac  resin  exists  in  the  bark  and  heartwood  of  a 
West-Indian  tree.  It  yields  protocatechuic  acid  when 
fused  with  potassium  hydroxide  and  is  decomposed  by 
destructive  distillation  into  guaiacol  and  allied  products. 

Crude    turpentine,    Burgundy    pitch    and    Copaiba    are 


154  ORGANIC    CHEMISTRY. 

natural  oleoresins,  the  consistency  being  liquid  or  semi- 
solid  according  to  the  amount  of  volatile  oil  associated  with 
the  resin. 

Balsams  are  oleoresins  which  are  associated  with  aro- 
matic products,  such  as  benzoic  or  cinnamic  acid.  The 
principal  balsams  are  Benzoin,  Balsam  Peru,  Balsam 
Tolu  and  Storax,  all  of  which  are  used  in  medicine. 

The  gum  resins  usually  exist  in  the  plants  from  which 
they  are  derived,  in  the  form  of  a  milky  juice.  Upon  fusing 
the  gum  resins  with  potassium  hydroxide  they  yield 
resorcin  and  protocatechuic  acid.  The  principal  gum 
resins  are  Asafetida,  Ammoniac,  Myrrh  and  Gamboge. 

Caoutchouc  and  gutta  percha  are  polyterpenes  which 
exist  in  many  plants  in  the  form  of  an  emulsion  or  milky 
juice. 

HETEROCYCLIC  COMPOUNDS. 

The  closed  chains  so  far  described  are  assumed  to  con- 
tain only  carbon  atoms.  Many  compounds  are  known  in 
which  the  ring  consists  of  carbon  atoms  with  an  atom  of 
oxygen,  sulphur  or  nitrogen.  These  are  termed  hetero- 
cyclic  compounds.  Nitrogen  carries  with  it  one  hydrogen 
atom  (see  Pyrrol). 

The  following  is  a  synopsis  of  the  most  important  groups 
of  this  type: 

THREE-MEMBERED  RINGS. — Among  these  are  found 
bodies  which  might  be  classed  as  open-chain  compounds, 
such  as  ethene  oxide,  C2H4O,  of  which  the  structural 

H2C^ 

formula  must  be:         I/O 
H2CX 

FOUR-MEMBERED  RINGS. — In  these  is  included  betaine, 
the  structural  formula  of  which  is  given  in  the  section  on 
Ptomaines.  The  ring  is  the  series  NOCC. 


HETEROCYCLIC    COMPOUNDS.  155 

FIVE-MEMBERED  RINGS. — These  include  several  im- 
portant types  of  compounds. 

Furfur ane:   four  carbon  and  one  oxygen  atom. 

Thiophene:   four  carbon  and  one  sulphur  atom. 

Pyrrol:    four   carbon   and  one   nitrogen   atom. 

Of  the  very  many  derivatives  that  these  bodies  may 
yield,  only  a  few  of  special  importance  can  here  be  noted. 

Furfurane,  C4H4O,  is  present  in  the  materials  collected 
from  the  distillation  of  pine  wood.  It  is  of  less  interest 
than  its  aldehyde. 

Furfural,  C4H3(HCO)O,  often  termed  furfurol,  is  pro- 
duced in  the  destructive  distillation  of,  or  action  of  strong 
acids  upon,  bodies  containing  carbohydrates,  and  in  small 
amount  in  alcoholic  fermentation.  Lately,  a  suggestion 
has  been  made  that  the  comparatively  higher  poisonous 
action  occasioned  by  newly-prepared  alcoholic  beverages 
is  due  to  furfural  and  not,  as  formerly  supposed,  to  or- 
dinary aldehyde  or  amyl  alcohols.  Furfural  is  a  colorless 
liquid  with  an  aromatic  odor.  It  has  well  marked  al- 
dehydic  properties.  It  is  used  for  a  few  special  tests  in 
food  analysis. 

Experiment  54. — Ten  grams  of  wheat  bran  are  mixed  in  a  500 
c.c.  flask  with  70  c.c.  of  water  and  3  c.c.  of  sulphuric  acid.  The 
flask  is  connected  with  a  condensing  arrangement  and  the  mixture 
cautiously  distilled  until  about  20  c.c.  have  passed  over.  The 
distillate  contains  furfural.  For  a  test  for  it,  see  under  Phenyl- 
hydrazin. 

Coumarin. — This  is  a  crystalline  principle  existing  in 
the  tonka  bean.  Its  odor  is  sufficiently  like  that  of  vanillin, 
to  cause  the  tonka  bean  to  be  used  very  much  as  a  sub- 
stitute for  vanilla.  The  molecule  of  coumarin  is  a  com- 
bination of  an  oxidised  furfurane  ring  with  a  benzene 
ring. 


156  ORGANIC    CHEMISTRY. 

Thiophene,  C4H4S,  may  be  regarded  as  benzene  in 
which  two  atoms  of  carbon  are  replaced  by  sulphur.  The 
principal  interest  attaching  to  it  is  that  it  is  a  frequent 
impurity  of  benzene.  It  gives  color  reactions  that  hy- 
drocarbons do  not  give,  but  its  presence  in  benzene  was 
long  unrecognised  and  its  reactions  were  ascribed  to 
benzene  itself  until  the  impurity  was  discovered.  Thio- 
phene  resembles  benzene  in  many  properties. 

Pyrrol,  C4H4NH,  is  found  in  bone  oil  and  coal-tar.  It 
can  be  prepared  synthetically.  It  is  a  colorless  liquid 
with  an  odor  recalling  that  of  chloroform. 

According  to  the  system  of  nomenclature  now  in  vogue 
the  termination  "ol"  is  not  appropriate  to  this  compound. 
The  name  "pyrrin"  would  be  more  systematic. 

SIX-MEMBERED  RINGS,  PYRiDiNS. — This  is  a  series  of 
bodies  that  contain  nitrogen  atoms  in  a  closed  chain  with 
carbon  atoms.  This  grouping,  known  as  the  "pyridin 
ring,"  is  a  stronger  molecular  linking  than  even  benzene, 
and  the  opportunities  for  isomerism  are  also  greater  than 
with  benzene.  The  type  compound  is: 

Pyridin,  C5H5N. — This  was  first  noted  in  the  offensive 
liquor  obtained  by  distilling  bones,  formerly  used  in 
medicine  under  the  name  "  Dippel's  animSl  oil."  It  is 
found  in  coal-tar.  Pyridin  is  a  liquid  with  a  disagreeable 
odor,  boiling  at  a  temperature  somewhat  above  that  of 
boiling  water.  It  is  a  monacid  base  combining,  as  is  usual 
with  nitrogen  bases,  with  the  entire  acid  molecule.  It  also 
unites  with  alkyl  iodides,  such  as  methyl  iodides;  these 
compounds  decomposed  by  silver  hydroxide,  yield  hydroxyl 
bases  analogous  to  the  substitution  ammoniums. 

Quinolin. — The  pyridin  ring  associated  with  a  benzene 
ring,  gives  rise  to  quinolin,  which  bears  the  same  struc- 
tural relation  to  pyridin  that  naphthalene  does  to  benzene. 


HETEROCYCLIC    COMPOUNDS.  157 

The  structural  formations  of  these  two  bodies  are  shown 
in  the  annexed  drawings  in  which  the  atoms  are  represented 
by  special  signs.  It  is  to  be  noted  that  while  pyridin  cannot 
exist  in  more  than  one  form,  since  the  nitrogen  atom  may 
be  placed  at  any  angle  of  the  chain  without  altering  the 
relations  of  the  other  atoms  to  it,  the  quinolin  group  is 
capable  of  two  modifications  as  shown.  Neither  pyridin 
nor  quinolin  contains  asymmetric  carbon  and,  therefore, 
has  no  optical  activity. 

Quinolin  is  a  colorless  liquid  of  high  dispersive  power. 
It  is  produced  in  the  destructive  distillation  of  coal,  bones 
and  many  alkaloids.  It  has  been  obtained  synthetically. 
Pyridin  and  quinolin  are  of  much  interest  not  only  on 
account  of  the  large  number  of  derivatives  they  yield,  but 
principally  because  their  molecular  structure  is  present 
in  many  alkaloids. 

H  H  H 


I 

H 

Quinolin 
The  round  dots  represent  carbon  atoms  ;  the  rectangular  represent 

nitrogen  atoms 
(Diagrammatic  formulas.) 

There  is  as  yet  no  uniform  method  of  representing  the 
pyridin  ring.  In  this  book  it  is  represented  by  benzene 
ring-symbol  with  a  small  "N"  attached  close  to  one  of  the 
angles,  as  shown  in  the  annexed  formula: 


158  ORGANIC    CHEMISTRY. 


H  H 

I  i 


r 


H  H 

Pyridin  symbol     Quinolin  symbol  Iso-quinolin 

=  C5H5N  "    =C9H7N 

Homologous  Derivatives. — The  hydrogen  of  all  these 
molecules  may  be  replaced  by  the  alkyl  radicles,  thus 
forming  homologous  series.  A  few  of  these  deserve 
mention. 

Methyl  Pyridins. — These  are : 

Picoline,  C5(CH3)H4N 
Lutidine,  C5(CH3)2H3^ 
Collidin,  C5(CH3)3H2N 

The  first  substitution  will  exist  in  three  forms,  the 
methyl  radicle  standing  either  in  the  1-2,  1-3  or  1-4  posi- 
tion to  the  nitrogen.  The  further  substitutions  will  show 
still  more  numerous  instances  of  isomerism. 

Additive  Compounds. — As  with  benzene  and  naphthalene 
the  latent  valencies  of  these  closed  chains  may  be  de- 
veloped, and  a  series  of  derivatives  obtained  in  which  the 
original  hydrogen  is  not  disturbed. 

Piperidin,  Pyridin  hydrid,  C5HUN,  is  closely  related 
to  conine,  as  the  annexed  formulas  show. 

Conine  is  a  substitution  of  propyl  (trityl),  C3H7,  for  the 
additive  hydrogen  atoms  in  piperidin  nearest  to  the 
nitrogen,  and  is  therefore,  1-2  propylpiperidin.  The 


HETEROCYCLIC    COMPOUNDS. 


159 


introduction  of  the  alkyl  radicle  makes  the  carbon  atom 
to  which  it  is  attached  asymmetric.  Conine  is  known  to 
exist  in  several  forms,  respectively,  dextro-  and  levo- 
rotatory,  and  inactive.  The  natural  conine  is  dextro- 
rotatory. 

H  H 


C3H7 


Pyridin  hydrid 
(Piperidin) 


Piperin. — This  substance  is  an  abundant  ingredient 
of  all  forms  of  pepper.  Its  empirical  formula  is  identical 
with  that  of  morphine,  but  it  is  not  an  alkaloid,  and  is 
structurally  wholly  different  from  morphine  as  the  an- 
nexed formula  shows.  It  contains  a  pyridin  and  a  ben- 
zene ring.  Piperin  must  not  be  confounded  with  the 
diamine,  piper  azin. 


O— CH2 


O 


Piperin 


CYANOGEN  AND  DERIVATIVES. 

Nitrogen  and  carbon  do  not  combine  by  simple  contact, 
but  if  nitrogen  be  passed  over  a  mixture  of  carbon  and 
potassium  carbonate,  potassium  cyanide,  KCN,  is  formed. 
From  this,  other  cyanides  may  be  obtained.  By  heating 
mercuric  cyanide,  Hg(CN)2,  free  cyanogen,  C2N2,  is  formed. 
This  is  a  colorless,  poisonous  gas. 

Cyanides  may  be  formed  from  proteid  matters.  This  may  be 
illustrated  by  placing  a  small  piece  of  dried  albumin  and  a  little 
sodium  in  the  closed  end  of  a  glass  tube,  heating  to  redness  for 
about  a  minute  and  dipping  the  heated  portion  into  a  little  water. 
The  tube  will  break  and  its  contents  partly  dissolve.  The  solution 
will  react  to  the  tests  for  cyanides,  as  given  below. 

Two  forms  of  cyanogen  compounds  are  known  termed, 
respectively,  cyanides  and  isocyanides,  as  follows: 

Potassium  cyanide.  Potassium  isocyanide. 

K— C=N  C=N— K 

In  the  former  nitrogen  is  triad,  in  the  latter,  pentad. 
Potassium  Cyanide,  KCN. — This  body,  prepared  usually 
by  decomposing  some  more  complex  cyanides,  is  a  snow- 
white  mass,  very  soluble  in  water,  and  easily  decomposed 
even  by  the  carbonic  acid  of  the  air,  hydrogen  cyanide 
being  formed.  Potassium  cyanide  dissolves  many  silver 
compounds  that  are  insoluble  in  water.  It  is  used  in 
making  solutions  for  silver-plating  and  in  photography, 
also  in  very  small  doses  as  a  medicine.  It  is  an  active 
poison.  Oxidising  agents  convert  it  into  potassium  cya- 
nate.  Commercial  potassium  cyanide  generally  contains 
cyanate  and  sodium  cyanide. 

1 60 


CYANOGEN    AND    DERIVATIVES.  l6l 

Hydrogen  Cyanide,  HCN. — This  is  generally  called 
hydrocyanic  or  prussic  acid.  When  pure,  it  is  a  colorless 
liquid,  easily  decomposed  and  intensely  poisonous,  As 
sold  for  medical  purposes  (Acidum  hydrocyanicum  dilu- 
timi),  it  is  very  dilute,  consisting  of  two  parts  of  acid  to 
ninety-eight  of  water.  It  has,  even  when  much  diluted, 
a  strong  odor  suggesting  bruised  peach  kernels  ;  in  fact, 
hydrogen  cyanide  is  formed  from  these  substances  by  the 
decomposition  of  nitrogenous  principles  when  the  seeds 
are  crushed  with  cold  water.  This  occurs  under  the  in- 
fluence of  enzyms,  for  if  these  are  first  coagulated  by 
boiling  alcohol,  no  decomposition  occurs.  The  reaction 
by  which  hydrogen  cyanide  is  formed  when  bitter  almonds 
are  macerated  with  water  consists  in  the  hydrolysis  of  a 
crystalline  principle  called  amygdalin,  under  the  in- 
fluence of  an  enzym  called  synaptase: 

Benzal-          Hydrogen 
Amygdalin.  dehyde.  cyanide.  Glucose. 

C20H27NOU    +    2H20    =  C7H60    +   HCN    +    2C6H12O6 

Hydrogen  cyanide  may  also  be  made  by  decomposing  other 
cyanides  by  strong  acids,  thus: 

2KCN    +   H2SO4    =   K2SO4   +   2HCN 
AgCN    +   HC1         =   AgCl      +    HCN 

The  latter  reaction  is  utilised  in  the  pharmaceutical 
preparation  of  the  dilute  acid. 

Complex  Cyanides. — The  potassium  group  cyanides 
show  a  great  tendency  to  combine  with  other  cyanides, 
especially  those  of  the  iron  group,  to  form  complex  cya- 
nides, in  which  some  properties  of  the  simpler  cyanides, 
especially  the  poisonous  qualities,  are  much  diminished. 
The  iron  series  is  the  most  important.  Two  well-marked 
compounds  are  known. 


162  ORGANIC    CHEMISTRY. 

Potassium  ferrocyanide,  K4C6N6Fe,  often  called  yellow 
prussiate  of  potash,  is  made  by  heating  a  mixture  of  nitrog- 
enous organic  matter,  iron  scraps,  and  potassium  car- 
bonate, treating  the  mass  with  water  and  allowing  it  to 
crystallise.  Large  lemon-yellow  crystals  are  formed, 
which  are  not  actively  poisonous.  Oxidising  agents 
convert  it  into: 

Potassium  ferricyanide  K3C6N6Fe,  commonly  called 
red  prussiate  of  potash.  It  forms  large  ruby-red  crystals, 
soluble  in  water.  The  reactions  with  some  substances 
are  so  distinct  as  to  constitute  very  delicate  tests.  With 
ferrous  compounds,  for  instance,  the  ferricyanides  give  a 
dark-blue  precipitate;  ferric  salts  give,  with  ferrocyanides, 
a  similar  blue  precipitate — Prussian  blue.  The  two 
precipitates  are  nearly  identical  in  composition.  An 
intermediate  compound  is  known  as  soluble  Prussian  blue, 
being  soluble  in  pure  water,  but  insoluble  in  water  con- 
taining ordinary  mineral  salts. 

Nitroprussic  acid. — By  the  action  of  nitric  acid  upon 
potassium  ferrocyanide,  an  acid-like  body  is  formed,  the 
structure  of  which  is  not  understood.  It  is  provisionally 
termed  nitroprussic  acid.  Its  importance  lies  in  the  fact 
that  its  sodium  salt,  Na2Fe(CN)5NO,  generally  called  so- 
dium nitroprussid,  is  a  test  for  sulphur  and  for  formaldehyde. 

Tests  for  Cyanides. — The  recognition  of  cyanogen  is  a 
matter  of  importance  in  toxicology.  The  tests  can  be 
directly  applied  only  to  the  simple  cyanides;  the  double 
cyanides  usually  give  the  reactions  after  being  decom- 
posed by  acids. 

Silver  nitrate  gives  a  white  precipitate  of  silver  cyanide, 
which  is  soluble  in  boiling  nitric  acid. 

A  mixture  of  ferrous  sulphate  and  sodium  hydroxide, 


CYANOGEN    AND    DERIVATIVES.  163 

when  agitated  with  a  cyanide  and  then  treated  with  acid, 
will  produce  a  blue  precipitate. 

When  hydrogen  cyanide  is  brought  into  contact  with 
ammonium  sulphide,  a  compound  called  ammonium 
thiocyanate  is  formed,  which  gives,  with  ferric  chloride  a 
blood-red  color. 

Experiment  55. — Dissolve  about  0.5  gram  of  potassium  cyanide 
in  20  c.c.  of  water.  Put  a  few  drops  of  this  solution  in  a  watch- 
glass,  add  a  drop  of  dilute  sulphuric  acid,  and  invert  over  the 
mixture  another  watch-glass  containing  a  drop  of  silver  nitrate 
solution.  Hydrogen  cyanide  will  be  formed  and  some  of  it  will  pass 
off  as  vapor  and  form  silver  cyanide  on  the  upper  glass. 

Experiment  56. — Repeat  Experiment  55,  substituting  a  drop 
of  ammonium  sulphide  for  the  silver  nitrate.  The  vapor  of  hydro- 
gen cyanide  will  form  ammonium  thiocyanate.  After  about  five 
minutes,  touch  the  spot  in  the  upper  glass  with  a  rod  dipped  in 
ferric  chloride.  A  bright  red  stain  of  ferric  thiocyanate  will  appear. 

Experiment  57. — To  5  c.c.  of  the  potassium  cyanide  solution, 
in  a  testtube,  add  a  few  drops  of  ferrous  sulphate  solution  and 
then  a  little  sodium  hydroxide.  A  precipitate  consisting  prin- 
cipally of  ferrous  hydroxide  forms.  Pour  the  mass  from  one 
testtube  to  another  ^for  a  short  time,  then  add,  cautiously,  hydro- 
chloric acid  in  slight  excess.  A  precipitate  of  ferric  ferrocyanide 
(Prussian  blue)  will  be  obtained.  This  is  destroyed  by  excess  of 
alkali  but  re-formed  by  acid. 

Experiment  58. — Heat  in  a  small  glass  tube,  sealed  at  one  end, 
a  small  amount  of  mercuric  cyanide.  Cyanogen  is  liberated  and 
will  burn  at  the  mouth  of  the  tube  with  a  characteristic  peach- 
blossom  flame.  At  the  upper  part  of  the  tube  a  brown  deposit 
of  a  polymeric  form,  termed  paracyanogen  will  collect. 

Cyanogen  hydroxides,  Cyanic  acids. — Cyanogen  unites 
with  hydroxyl  to  form  several  compounds  that  have  the 
same  percentage  composition,  but  some  are  stereo-isomers, 
others  polymers.  Both  forms  of  cyanogen  form  these 
compounds.  Three  important  forms  are: 

:      N=C— O— H         H— N=C=O         C=N— O— H 
Cyanic  acid  Isocyanic  acid  Fulminic  acid 


164  ORGANIC    CHEMISTRY. 

Cyanuric  acid,  H3C3N3O3,  is  of  more  complex  structure. 
Fulminuric  acid  has  the  same  empirical  formula  as  cyanuric 
acid,  but  is  a  nitro-derivative  and,  therefore,  of  entirely 
different  type. 

The  important  derivatives  of  these  acids  are  the  cyanates 
and  fulminates. 

Potassium  cyanate. — The  common  cyanate  is  isocyanate, 
KNCO.  It  exists  in  considerable  amount  in  commercial 
potassium  cyanide  and  can  be  obtained  by  heating  cyanides 
with  lead  oxides. 

Ammonium  cyanate,  NH4NCO,  is  of  interest  because  it 
may  be  transformed  by  heating  into  urea,  (NH2)2CO. 
This  transformation  was  the  first  instance  of  organic 
synthesis  and  its  accomplishment  broke  down  the  lines 
between  organic  and  inorganic  chemistry.  The  change 
is  a  rearrangement  as  follows: 

H     O     H 

I      H      I 
H4N— N  =  C=O  H— N— C— N— H 

Ammonium  cyanate  Urea 

Fulminates. — As  the  name  indicates,  many  of  these 
are  explosive.  Mercuric  Culminate,  Hg(CNO)2,  is  prepared 
by  heating  a  mixture  of  alcohol,  nitric  acid  and  mercuric 
nitrate.  It  crystallises  in  needles.  It  explodes  violently 
on  percussion,  and  is  the  material  used  in  percussion  caps 
for  firearms. 

Silver  Culminate,  AgCNO,  is  more  explosive  than  the 
mercuric  salt. 

Thiocyanates . — These  compounds,  often  called  sulpho- 
cyanates,  are  analogous  to  the  cyanates  and  are  obtained 
in  a  similar  manner,  that  is,  by  direct  addition  of  sulphur, 


CYANOGEN    AND    DERIVATIVES.  165 

but  the  molecular  arrangement  is  not  identical  in  the  two 
actions. 

The  common  cyanate  is  isocyanate,  as  already  noted 
(See  formula  of  potassium  cyanate.)  Oxygen  attaches  itself 
in  preference  to  the  carbon  and  nitrogen  atoms,  but  sulphur 
attaches  itself  to  the  other  positive  element,  hydrogen  or 
metal.  The  contrast  is  shown  in  the  structural  formulas: 


K—  N=  C=O  N=C—  S—  K 

Common  potassium  cyanate         Common  potassium  thiocyanate 
(Isocyanate) 

The  soluble  thiocyanates  produce  with  ferric  com- 
pounds a  bright  red  solution  of  ferric  thiocyanate.  This 
reaction  is  a  delicate  test  for  ferric  compounds.  No  color 
is  produced  with  ferrous  compounds. 

The  known  esters  of  thiocyanic  acid  are  of  the  iso- 
thiocyanic  type.  They  are  sometimes  termed  "  mustard 
oils,"  as  the  volatile  oil  of  black  mustard  is  allyl  iso- 
thiocyanate,  (C3H5)NCS.  As  noted  elsewhere,  it  does 
not  exist  in  the  seed,  but  is  produced  by  a  decomposition 
under  the  influence  of  a  special  enzym. 

H2Cn:C  —  CH2 

H    N 

II 
s=c 

Allyl  isothiocyanate 
(Mustard  oil) 

Azoimide,  Hydr  azoic  acid.  —  An  interesting  connecting 
link  between  inorganic  and  organic  chemistry  is  furnished 
by  this  substance.  It  has  the  empirical  formula  N3H. 
The  structural  formula  is  considered  to  be  : 


l66  ORGANIC    CHEMISTRY. 

N=N  N=N 

V  V 

NH  N— NH4 

Azoimide  Ammonium  hydrazoate 

(Hydrazoic  acid) 

It  was  first  prepared  from  an  amine  derivative  of  benzene, 
benzoyl  nitride,  by  treatment  with  sodium  ethylate,  the 
following  reaction  occurring: 

Sodium  ethylate.  Benzoyl  nitride.    Sodium  hydrazoate      Ethyl  benzoate. 

NaC2H5O      +      C6H5CON3      =     NaN3      +     C6H5CO2C2H5 

Hydrazoates  may  be  prepared  by  several  other  methods 
some  of  which  are  not  strictly  organic.  From  the  salt 
the  hydrogen  compound  may  be  obtained.  It  is  a  color- 
less mobile  liquid  of  very  disagreeable  odor,  and  highly 
explosive.  It  resembles  the  halogen  acids  in  many 
properties.  Its  ammonium  salt,  NH4N3,  has  the  em- 
pirical formula  H4N4. 


AMMONIUM    DERIVATIVES. 

Amines  and  Amides. — Amine,  NH3,  ammonia,  is  al- 
ways found,  either  free  or  combined,  among  the  products  of 
decomposition  of  nitrogenous  matter.  One  of  the  most 
striking  properties  of  free  amine  is  its  power  to  neutralise 
acids.  When  certain  organic  bodies  containing  nitrogen 
were  found  to  have  a  similar  property,  a  similar  con- 
stitution was  assigned  to  them.  Morphine  and  quinine, 
which,  like  amine  are  decidedly  alkaline,  and  contain 
considerable  nitrogen,  have  been  regarded  as  ammoniacal 
in  character.  Although  efforts  to  produce  these  bodies 
synthetically  have  succeeded  only  to  a  limited  extent, 


AMMONIUM     DERIVATIVES.  167 

yet  many  substances  resembling  them  in  composition  have 
been  obtained,  and  no  doubt  need  now  exist  as  to  the  es- 
sential nature  of  these  products,  or  as  to  the  possibility  of 
ultimately  producing  them.  Many  of  the  synthetic  bases 
now  known  are  produced  by  the  substitution  of  the  hy- 
drogen or  nitrogen  in  amine,  NH3,  or  ammonium,  NH4,  by 
different  elements  or  radicles.  The  number  of  compounds 
so  produced  is  greatly  increased  by  the  fact  that  these 
molecules  are  capable  of  polymerism,  so  that  one  set  of 
compounds  may  be  formed  on  the  type  NH3,  and  another 
on  that  of  N2H6,  and  so  on.  A  very  complete  and  syste- 
matic nomenclature  has  been  adopted  for  these  compounds. 
In  the  first  place,  the  character  of  the  replaceable  radicles, 
and,  to  a  certain  extent,  therefore,  the  character  of  the 
compound  itself,  is  indicated  by  the  termination.  When 
the  radicle  is  positive,  and  especially  when  it  does  not 
contain  oxygen,  "ine"  is  used;  when  negative  and  con- 
taining oxygen,  " lide"  is  used.  When  the  nitrogen  is 
replaced  by  some  member  of  its  group  (B,  P,  As,  Sb  and 
Bi),  some  distinct  syllables  of  these  names  are  added. 
The  names  of  all  the  radicles  entering  into  the  compound 
are  attached.  If  the  molecule  is  duplicated,  the  syllables 
"di,"  lltri,"  etc.,  are  used  to  indicate  the  degree  of  dupli- 
cation. If  the  compound  is  derived  from  the  type  NH4 
it  has  the  termination  "onium."  The  following  list  will 
show  all  these  points: 

NH3,  amine;  N2H6,  diamine;   N3H9,  triamine;   N4H12,  tctramine. 

PH3,  phosphine;   P2H6,  diphosphine. 

AsH3,  arsine. 

SbH3,  stibine. 

NH4,  ammonium;   N2H8,  diammomum;   N:JH12,  triammonium. 

PH4,  phosphonium. 

AsH4,  arsonium. 

SbH4,  stibonium. 


l68  ORGANIC    CHEMISTRY. 

The  polymerisation  of  the  molecules  takes  place  by 
introduction  of  radicles  of  dyad  or  higher  valency.  The 
methods  of  producing  these  substitution  compounds  are 
various;  one  of  the  simplest  is  by  heating  solutions  of 
amine  with  bromides  or  iodides  of  the  radicles  to  be  sub- 
stituted. Thus,  an  alcoholic  solution  of  amine  and  ethyl 
iodide  heated  for  some  hours  in  a  sealed  tube,  gives  the 
reaction : 

NH3   +    (C2H5)I    =    (C2H5)H3NI 

As  NH4I  is  ammonium  iodide  so  the  above  compound  is 
called  ethylammonium  iodide.  By  further  action  the 
whole  of  the  hydrogen  may  be  replaced  by  ethyl,  and  we 
get  (C2H5)4NI,  tetrethylammonium  iodide.  Each  of  the 
hydrogen  atoms  may  be  replaced  by  a  different  radicle, 
by  which  great  complexity  in  structure  and  nature  arises. 
Thus: 

(C2H5)2(C5H11)HNI diethylpentylammonium  iodide. 

(C2H5)3(C5H11)NI     triethylpentylatnmonium  iodide. 

(CH3)(C2H5)(C3H7)(C4H9)NI  .  .  .  methylethylpropylbutylammonium 

iodide. 

From  NH3  we  may  derive: 

(C2H5)H2N ethylamine. 

(C2H5)2HN diethylamine. 

(C2H5)3N    triethylamine. 

When  but  one-third  of  the  hydrogen  is  substituted,  the 
body  is  said  to  be  primary;  when  two-thirds  are  substi- 
tuted, it  is  secondary;  when  all  is  substituted,  the  body 
is  tertiary.  Ethylamine  for  instance,  is  a  primary  mon- 
amine.  The  following  structural  formulas  show  some  of 
these  bodies : 


AMMONIUM     DERIVATIVES.  169 

H 


H— C— H 


CH3  H3C   CH3 

I  I  v 

H— N— H        H8C— N— CH8    H3C— N— CH3 


Methylamine  Trimethylamine  Tetramethylammonium 

chloride 

Diamines  and  diammoniums.     These  always  contain  N2 : 

(C2H4)H4N2 ethenediamine  (ethylenediamine) . 

(C2H4)H6N2(HO)2    ethenediammonium  hydroxide. 

Triamines,  and  triammoniums ,  tetr amines  and  tetr am- 
moniums, are  formed  on  the  same  principle. 

The  following  formulas  show  some  of  the  compounds 
obtained  by  these  elaborate  substitutions  and  when  the 
nitrogen  is  replaced  by  other  members  of  its  group : 

Ethyl  phosphine.  Diethyl  phosphine.          Triethyl  phosphine. 

(C2H5)H2P  (C2H5)2HP  (C2H5)3P 

Trimethyl  arsine.  Tripentyl  stibine.  Triethyl  bismine. 

(CH3)3As  (C4Hn),Sb  (C2H5)3Bi 

Triethyl  borine. 

(C2H5)3B 

Tetrethylphosphonium  hydroxide.  Tetrethylstibonium  iodide. 

P(C2H5)4HO  Sb(C2H5)4I 

By  a  combination  of  radicles  of  different  valencies  we 
may  get  such  a  body  as: 

(CH3)3(C2H5)3(C2H4)H4P3I3,      trimethyltriethylethenetriphosphon- 
ium  iodide. 

Several  complex  amines  are  used  in  medicine.  Among 
these  are : 


I  70  ORGANIC    CHEMISTRY. 

Hexmethenetetramine,  (CH2)6N4,  which  is  made  by  adding 
ammonium  hydroxide  to  formaldehyde.  The  reaction 
is  a  dehydrolysis : 

6CH20    +    4NH4HO    ..    (CH2)6N4    +    ioH2O 

The  product  is  a  colorless,  almost  inodorless,  crystalline 
mass,  soluble  in  water.  It  is  now  sold  under  proprietary 
names — e.  g.,  formin,  cystogen,  urotropin — for  the  treat- 
ment of  purulent  affections  of  the  kidneys  and  bladder. 
When  taken  internally  it  is  decomposed  into  formaldehyde 
and  ammonium  hydroxide.  The  former  is  largely  excreted 
by  the  kidneys  and  thus  exercises  its  antiseptic  action 
over  the  mucous  membranes  of  the  genito-urinary  tract. 

Experiment  59. — To  10  c.c.  of  commercial  formaldehyde  solu- 
tion add  small  amounts  of  ammonium  hydroxide,  testing  between 
each  addition  by  a  drop  of  the  solution  on  red  litmus  paper,  until 
the  reaction  becomes  alkaline.  Allow  the  mixture  to  stand  for 
some  hours  and  then  evaporate  it  at  a  low  temperature.  The 
tetramine  will  separate  as  a  white  crystalline  mass. 

Piper azin  is  ethenediamine  (ethylenediamine).  It  forms 
yellowish  crystals,  soluble  in  water.  It  is  strongly  basic, 
and  has  been  used  in  the  treatment  of  diseases  supposed 
to  be  associated  with  excessive  excretion  of  uric  acid,  as 
piperazin  urate  is  very  soluble  in  water.  Piperazin  must 
not  be  confounded  with  piperin. 

H     H 


H— C— C— H 
H— N  N— H 
H— C— C— H 


H    H 

Piperazin 


AMMONIUM     DERIVATIVES.  171 

Amides.^ — All  primary  monamines  may  be  expressed  as 
substitutions  of  amidogen,  NH2,  for  other  monads.  When 
the  amidogen  is  associated  with  a  substantially  positive 
group,  the  compound  is  basic  and  is  called  an  amine,  but 
when  associated  with  negative  groups  it  may  form  either 
acid  or  neutral  bodies  which  are  called  amides.  Thus, 
amidogen  may  be  substituted  for  the  hydrogen  of  benzene, 
giving  rise  to  C6H5NH2,  amidobenzene,  which  is  basic,  and 
is  therefore  an  amine.  Substituted  for  the  hydrogen 
of  acetic  acid  it  gives  amidoacetic  acid,  in  which  some  of 
the  acid  properties  are  retained;  but  substituted  for  the 
hydroxyl  of  acetic  acid  it  entirely  removes  the  acid  func- 
tion, forming  a  body  called  acet amide.  These  facts  are 
shown  by  structural  formulas: 

HO  HO 

H            |      ||  |      ||            H 

>  N— C— C— O— H  H— C— C— N  < 

H|  I                   H 

H  H 

Amidoacetic  acid  Acetamide 

Urea,  carbonyl  diamide,  (NH2)2CO,  is  the  most  abun- 
dant solid  ingredient  of  normal  human  urine.  It  is  a  color- 
less solid,  crystallising  readily  and  is  freely  soluble  in  water 
and  alcohol.  Most  of  its  salts  are  also  soluble,  but  the 
nitrate  and  oxalate  are  but  sparingly  so,  hence  the  ad- 
dition of  nitric  or  oxalic  acid  to  urines  rich  in  urea  will 
produce  a  precipitate.  Urea  is  strictly  a  diamide,  that 
is,  formed  by  the  substitution  of  an  acid  radicle — the 
group  CO — but  this  overcomes  only  one  of  the  amidogen 
groups,  hence  urea  forms  salts  with  one  equivalent  of 
acid,  not  as  do  the  diamines  with  two  equivalents.  As 
with  all  other  compounds  of  these  types,  the  whole  mole- 


172  ORGANIC    CHEMISTRY. 

cule  of  the  acid  acts;  urea  hydrochloride  is  CH4N2O,HC1. 
The  following  structural  formulas  will  show  the  relation  of 
urea  to  carbonic  acid  through  the  intermediate  body, 
carbamic  acid: 

o 

H-0  || 

H— O  >C=0  C 

>C=O     H— N  A 

H— O  I  H— N    N— H 

H  I      | 

H   H 

Carbonic  acid  Carbamic  acid  Urea 

Urea  is  not  liable  to  decomposition  when  in  pure  solu- 
tion, but  in  presence  of  proteid  matters  and  exposed  to  the 
air  it  soon  hydrolyses  to  ammonium  carbonate.  This 
is  the  ordinary  reaction  by  which  urine  becomes  alkaline 
on  standing: 

CH4N20    +    2H2O    =    (NH4)2CO3 

This  change  is  due  to  enzyms  formed  by  microbes. 

Urea  is  decomposed  by  hypochlorites  and  hypobromites 
with  evolution  of  carbon  dioxide  and  nitrogen.  This 
reaction  is  utilised  in  the  quantitative  determination  of 
urea  in  urine.  Urea  can  be  prepared  synthetically  by 
heating  ammonium  cyanate.  This  was  the  first  discov- 
ered instance  of  synthesis.  The  change  is  merely  a  re- 
arrangement. (See  under  Cyanates.) 

Experiment  60. — Melt  in  a  sand  crucible  of  about  50  c.c.  capac- 
ity, 10  grams  of  commercial  potassium  cyanide  and  stir  in,  grad- 
ually and  slowly,  40  grams  of  lead  monoxide  (litharge).  When 
the  entire  amount  has  been  added  pour  the  mass  out  upon  an 
iron  plate,  and  allow  to  cool.  Separate  as  far  as  possible  the 
reduced  lead  from  the  potassium  cyanate  that  has  been  formed; 
powder  the  latter  and  dissolve  in  50  c.c.  of  cold  water,  filtering 


AMMONIUM    DERIVATIVES.  173 

if  necessary.  Add  a  cold  saturated  solution  of  12  grams  of  am- 
monium sulphate,  heat  the  mixture  slowly  on  the  water-bath  to 
a  temperature  of  60°  and  maintain  it  at  that  point  for  an  hour. 
The  ammonium  cyanate  which  is  the  first  product  of  the  reaction 
is  changed  to  urea.  This  may  be  obtained  by  evaporating  the 
solution  to  dryness  in  shallow  basins  on  the  water-bath  and  ex- 
tracting the  residue  with  boiling  alcohol.  The  urea  crystallises 
from  the  cold  alcohol.  It  is  not  quite  pure  but  will  show  the 
characteristic  properties. 

Many  complex  bodies  of  these  types  are  found  in  the 
fluids  of  living  tissues  and  among  products  of  putrefaction. 
Some  of  these  are  described  in  the  section  on  Purins, 
others  in  the  section  on  Ptomaines  and  Leucomaines. 
Some  others  of  considerable  importance  are  here  described. 

Taurin,  amidothylsulphonic  acid,  C2H4(NH2)HSO3,  is  ob- 
tained by  hydrolysis  of  taurocholic  acid  of  bile,  especially 
ox  bile,  by  hydrochloric  acid,  forming  taurin  and  cholic 
acid.  Taurin  forms  colorless  crystals  very  soluble  in 
water.  As  it  contains  NH2  and  HSO3  it  has  both  acid 
and  basic  properties. 

Amidoacetic  acid,  glycocoll,  glycin,  HC2H2(NH2)O2. — 
This  may  be  obtained  by  several  methods,  among  which 
are  boiling  glue  with  sulphuric  acid,  warming  monochlor- 
acetic  acid  with  dry  ammonium  carbonate,  and  decom- 
position of  glycocholic  acid  (of  bile)  by  potassium  hydrox- 
ide. Amidoacetic  acid  is  a  crystalline  solid,  soluble  in 
water;  the  solution  has  a  sweetish  taste.  It  is  both  an 
acid  and  a  base.  It  easily  forms  salts  with  ordinary  posi- 
tives and  also  combines  with  common  acids  forming, 
for  example,  the  following  compounds:  CuC2H4NO2  and 
C2H5NO2HC1,  both  of  which  are  crystalline  bodies. 

Amidoacetic  acid  forms  esters  with  the  alkyl  radicles 
and  also  amine  derivatives  of  which  the  following  will 
serve  as  examples: 


174  ORGANIC    CHEMISTRY. 

Ethyl  amidoacetate  ,  C2H5C2H4NO2.  —  This  is  a  volatile 
liquid  with  an  odor  resembling  that  of  cacao. 

Methylamidoacetic  acid,  HC2H2NH(CH3)O2,  methyl  glyco- 
coll,  sarkosin,  was  first  obtained  as  a  decomposition  pro- 
duct of  kreatin. 

HHO        HH  HHO 

I      I     II         V  I      I     II 

N—  C—  C—  O—  C  N—  C—  C—  O—  H 

H    H  H         H—  C     H 


Methyl  amidoacetate  Methylamidoacetic  acid 

(Sarkosin) 

Hippuric  acid,  benzoyl  glycocoll.  —  The  structural  formula 
of  this  shows  that  it  contains  residues  of  both  amidoacetic 
acid  and  benzoic  acid;  in  fact,  its  empirical  formula  may 
be  obtained  by  adding  the  formulas  of  these  acids  and 
deducting  H2O.  By  hydrolysis  and  also  by  the  action  of 
acids  or  alkalies,  hippuric  acid  may  be  decomposed  into 
benzoic  acid  and  amidoacetic  acid.  As  hippuric  acid 
occurs  in  considerable  proportion  in  the  urine  of  herbiv- 
orous animals,  it  has  been  a  commercial  source  of  ben- 
zoic acid. 


O=C— O— H 

Hippuric  acid. 


AMMONIUM     DERIVATIVES.  175 

Trimethyl  glycocoll  is  betaine,  a  ptomaine  described  in 
another  section. 

Amido-derivatives  of  the  higher  acids  exhibit  numerous 
instances  of  isomerism.  Among  these  are: 

Leucins. — Under  the  name  leucins  several  analogous 
substances  with  the  empirical  formula,  C6H13NO2,  have 
been  included.  They  are  found  among  the  products  of 
digestion  of  proteids,  especially  under  the  influence  of 
trypsin,  and  are  often  associated  with  tyrosin. 

One  form  of  leucin,  probably  an  amidocaproic  acid,  is 
derived  from  casein  and  has  also  been  prepared  synthet- 
ically; another  form  is  a  derivative  of  butylacetic  acid. 
Some  of  these  forms  contain  asymmetric  carbon  and  are, 
therefore,  optically  active. 

Tyrosin,  1-4  phenolamidopropionic  acid. — This  is  pro- 
duced in  many  transformations  of  proteid  matters,  such  as 
boiling  horn,  hair  or  albumin  with  sulphuric  acid,  digesting 
proteids  for  some  time  with  pancreatic  secretion  and  by 
putrefactive  actions.  It  has  been  prepared  synthetically. 

HO 


H— C— H 
i 

,H 


H— C— 

I 
O=C— O— H 

Tyrosin 

Cystin,  C6H12N2O4S2,  probably  an  amidothiolactic  acid 
derivative  occurs  as  a  crystalline  sediment  in  human 
urine  and  sometimes  forms  a  calculus. 

Asparagin  is  an  example  of  the  presence  of  amidogen 


176  ORGANIC    CHEMISTRY. 

in  two  positions  in  a  molecule.  It  is  succinic  acid  with  one 
hydroxyl  group  replaced  by  amidogen,  and  another  amido- 
gen group  replacing  a  hydrogen  atom  attached  to  carbon 
so  that  both  the  amine  and  amide  structures  are  exhibited. 
Asparagin  has  asymmetric  carbon.  It  is  found  in  the  seeds 
of  many  plants  and  in  the  sprouts  of  asparagus  and  vetch. 
The  asparagin  in  asparagus  is  levorotatory;  that  in  vetch 
is  mostly  the  same,  but  the  dextrorotatory  form  also  is 
found.  The  natural  occurrence  of  a  levorotatory  body 
in  predominating  quantity  is  unusual,  since  most  natural 
bodies  that  are  optically  active  are  dextrorotatory. 

H   H 

v 

O    N     H    O    H 

II      I       I      II      I 
C— C— C— C— N 


O    H    H 


H 

Amido-succinamic  acid 
(Asparagin) 

Purins,  Alkaloids,  Ptomaines,  Leucomaines . — These  are 
groups  of  nitrogenous  compounds  many  of  which  are 
amines  or  amides.  The  important  bodies  of  each  type 
are  described  in  connection  with  the  group  named. 

Azo-,  DIAZO-  AND  HYDRAZO-COMPOUNDS. 

When  two  atoms  of  nitrogen  are  joined  by  two  bonds, 
and  the  remaining  bonds  are  joined  to  similar  radicles, 
a  group  is  formed  called  an  azo-compound.  When  the 


AZO-,    DIAZO-    AND    HYDRAZO-COMPOUNDS.  177 

radicles  are  dissimilar,  a  diazo-cornpound  (diazonium) 
is  formed.  When  an  atom  of  oxygen  is  inserted  between 
the  nitrogen  atoms,  an  azoxy-compound  is  formed.  When 
one  bond  of  each  nitrogen  atom  is  united  to  an  atom  of 
hydrogen,  the  body  is  called  a  hydrazo-compound.  These 
points  are  exemplified  in  the  following  formula: 

=  N—  N=  _N=zN—  9 

—  N-N— 

Hydrazo-  group  Azo-  group  Azoxy-  group 


HN—  NH2  HN  -  NH 


Diazobenzene  Phenylhydrazin  Hydrazobenzene 

(diazonium)  sulphate 

Hydrazins. — The  hydrazins  agree  with  the  diazo- 
compounds  in  containing  dissimilar  radicles,  but  differ 
in  the  fact  that  the  union  between  the  nitrogen  is  by  one 
bond  only. 

The  difference  is  shown  in  the  following  formulas : 

Diazo-benzene  nitrate.  Phenylhydrazin  nitrate. 

C6H5N  =  N—  (NO,)         C6H5N— N(N03) 

H     H3 

Azo-compounds  are  now  of  considerable  practical 
importance.  Many  of  them  are  brilliant  in  color  and  less 
liable  to  fade  than  some  of  the  other  forms  of  synthetic 
colors.  Some  of  them  have  the  valuable  property  of  dyeing 
cotton  without  a  mordant.  A  few  are  quite  insoluble 
in  water  but  soluble  in  oil. 


178  ORGANIC    CHEMISTRY. 

Azo-  derivatives  are  usually  produced  through  the 
intermediate  development  of  diazo-compounds,  by  reac- 
tion of  amine  derivatives  with  nitrous  acid.  This  method 
called  "diazotising,"  was  discovered  by  Griess.  It  is 
regularly  used  in  manufacturing  operations,  the  nitrous 
acid  being  obtained  by  the  action  of  a  strong  acid,  acetic, 
sulphuric  or  hydrochloric,  on  sodium  nitrite. 

A  few  of  the  azo-  colors  are  insoluble  in  water  but  soluble 
in  alcohol  and  in  oils.  They  are  used  for  coloring  fatty 
foods,  especially  butter  and  butter-substitutes.  Several 
of  them  have  been  designated  by  the  fanciful  term  Soudan, 
and  distinguished  by  appended  letters,  as  noted  in  the 
general  description  of  synthetic  colors. 

Soudan  I  istoetanaphtholazobenzene,  C6H5N=  NC10H6OH. 

These  derivatives  are  capable  of  "sulphonation,"  that 
is,  conversion  into  sulphonic  acids  by  treatment  with 
sulphuric  acid.  By  this  means  many  of  them  are  ren- 
dered more  soluble  and,  apparently,  in  a  few  instances,  less 
toxic.  From  the  sulphonic  acids  salts  may  be  formed  with 
any  of  the  metals,  and  thus  derivatives  analogous  to  the 
mineral  salts  are  obtained. 

Methyl  orange,  helianthin,  Porrier's  tropeolin  D,  Orange 
III,  gold  orange,  mandarin  orange. — Sodium  dimethyl  1—4 
amido-azobenzenesulphonate.  This  series  of  commercial 
synonyms  is  given  merely  as  an  instance  of  the  nomen- 
clature of  these  bodies.  Methyl  orange  is  the  ordinary 
name.  Its  composition  is  seen  from  the  structural  for- 
mula, but  obviously  other  positive  elements  can  replace 
sodium,  giving  derivatives  of  the  same  type  but  slightly 
different  in  properties.  Methyl  orange  dyes  bright  orange. 
It  is  used  in  coloring  textiles  and  sometimes  in  foods, 
and  has  a  special  use  as  an  indicator  in  acidimetry  and 
alkalimetry.  It  is  an  orange-yellow  powder,  freely  soluble 


AZO-,    DIAZO-    AND    HYDRAZO-COMPOUNDS.  179 

in  water,  producing  a  yellow  solution  which  becomes  red- 
orange  by  addition  of  any  mineral  acid. 

N=  =N 


NaSO3       N(CH3)2 
Methyl  orange 

Bismarck  brown  is  the  hydrochloride  of  a  complex  azo- 
derivative.  It  is  used  for  coloring  imitation  wines,  fruit 
juices  and  in  confectionery,  as  well  as  in  dyeing  textiles. 

Congo  Red.  —  This  color  belongs  to  a  group  termed 
"  tetrazo-compounds  "  because  they  contain  the  azo- 
group  twice.  The  term  diazo  is  appropriated  to  a  special 
form  of  azo-compounds.  The  tetrazo-compounds  are 
chiefly  interesting  to  dyers,  but  Congo  red,  the  structural 
formula  of  which  is  here  shown,  is  used  in  the  laboratory 
as  an  indicator,  having  the  striking  property  of  assuming 
colors  the  reverse  of  litmus  and  other  common  vegetable 
colors.  Congo  '  red  is  blue  in  acid  solution  and  red  in 
alkaline.  It  is  not  a  very  delicate  indicator,  but  is  much 
used  in  testing  stomach-contents  for  free  hydrochloric 
acid.  It  dissolves  in  water.  It  is  used  generally  in  the 
form  of  test-papers. 

NH,  NaSO3 


=N<       \/     \N=N 


NaSO,   "  '       NH, 

Congo  red 

The  addition  of  a  strong  acid  liberates  the  free  sulphonic 
acid  which  is  blue,  but  its  salts  are  red. 


l8o  ORGANIC    CHEMISTRY. 

DIAZO-COMPOUNDS. — As  previously  noted,  this  term  is 
applied  when  the  nitrogen  atoms  are  united  by  more  than 
one  bond  and  the  residual  bonds  are  not  in  union  with  the 
same  type  of  radicle.  The  exact  nature  of  the  molecular 
structure  has  been  disputed  among  chemists.  Present 
opinion  tends  to  regard  them  as  more  closely  analogous 
to  ammonium  than  to  amine,  and  hence  they  are  often 
termed  "diazonium"  compounds.  The  difference  between 
these  views  is  shown  in  the  formulas  for  diazobenzene 
chloride : 

Amine  type.  Ammonium  type. 

C6H5N  =  N— Cl  C6H5— N— Cl 

N 

These  compounds  are  generally  unstable.  Many  of  them 
are  explosive  and  some  highly  poisonous.  It  has  been 
thought  that  some  are  formed  in  the  putrefaction  of  pro- 
teids,  especially  milk-proteids,  and  that  this  accounts  for 
the  violently  poisonous  properties  of  some  spoiled  foods. 
They  do  not  appear  to  be  present  in  advanced  states  of 
putrefaction,  but  when  the  food  is  merely  stale.  As  they 
are  mostly  easily  decomposed  by  heat,  cooking  of  such 
food  often  takes  away  the  poisonous  action.  In  the  com- 
mon cases  of  cheese  and  ice-cream  poisoning,  diazo-ben- 
zene  (diazonium)  salts  have  been  supposed  to  be  present, 
and  one,  provisionally  termed  "  tyrotoxicon "  (Gr.  cheese- 
poison),  may  be  diazobenzene  butyrate  (diazonium  buty- 

O N=N 


C3H7 

Diazobenzene  butyrate 
(Tyrotoxicon) 


AZO-,    DIAZO-    AND    HYDRAZO-COMPOUNDS.  l8l 

rate),  the  structural  formula  of  which  is  annexed,  but  the 
products  will  differ  with  different  conditions.  The  small 
amounts  in  which  the  bodies  are  produced  and  the  ease 
with  which  they  are  decomposed,  makes  identification  of 
them  uncertain. 

The  hydroxides  of  the  group  are  unstable  but  they  form 
derivatives  analogous  to  sodium  ethylate  which  are  not  so 
easily  decomposed.  For  example,  a  potassium  compound 
of  the  empirical  formula,  C6H5N2OK,  is  known.  Esters  have 
also  been  prepared.  These  bodies  have  as  yet  little 
practical  importance,  but  it  is  not  improbable  that  use- 
ful high  explosives  may  be  prepared  from  some  members 
of  the  group. 

Experiment  61. — Prepare  the  following  solutions.  The  pro- 
portions given  are  suggestive  only;  it  is  not  necessary  to  adhere 
strictly  to  them: 

0.05  gram  phloroglucol  in  5  c.c.  alcohol; 

0.05  gram  vanillin  in  5  c.c.  alcohol; 

o.i  gram  sulphanilic  acid  in  10  c.c.  of  water  and  5  c.c.  hydro- 
chloric acid; 

o.i  gram  alphaamidonaphthalene  in  10  c.c.  of  water  and  5  c.c. 
hydrochloric  acid; 

o.i  gram  sodium  nitrite  in  10  c.c.  of  water; 

o.i  gram  betamidonaphthalene  in  10  c.c.  of  water  and  5  c.c. 
of  hydrochloric  acid. 

The  solution  of  sulphanilic  acid  and  amidonaphthalenes  may 
be  slow.  It  will  not  be  necessary  to  wait  until  all  the  material  is 
dissolved.  Care  should  be  taken  not  to  get  the  alphaamidonaph- 
thalene on  the  hands,  as  it  has  a  persistent,  disgusting  odor. 
The  sodium  nitrite  solution  should  be  fresh.  The  others  keep 
well. 

Experiment  62. — To  10  c.c.  of  water  add  i  drop  of  the  sodium 
nitrite  solution  and  then  about  i  c.c.  each  of  the  solutions  of 
sulphanilic  acid  and  alphaamidonaphthalene.  A  pink  tint  will 
soon  appear  and  deepen  in  about  ten  minutes. 

Experiment  63. — Repeat  Experiment  62,  using  no  sodium 
nitrite.  No  color  will  appear. 


182  ORGANIC    CHEMISTRY. 

The  changes  that  occur  in  Experiment  62  are  as  follows: 
NH, 

+  HNO2= 
HS03  S03 

1-4  amidobenzenesul-     Diazobenzenesulphonic 

phonic  acid  anhydride 

(Sulphanilic  acid) 

The  diazo-compound  reacts  with  the  amidonaphthalene 
to  produce  the  azo-derivative  as  follows: 

C6H4N=NS03  +  C10H7NH2   =  C10H6(NH2)N  =NC6H4HSO3 

Alpha-azo-amidonaphthaleneparazo- 
benzenesulphonic  acid 

The  above  reactions  are  analogous  to  those  occurring 
in  a  urine  test  now  much  used  under  the  name  "Ehrlich's 
diazo-reaction."  This  depends  on  the  formation  of  a  red 
azo-derivative  by  the  reaction  of  the  diazo-compound 
produced  in  the  above  manner  with  bodies  not  yet  iso- 
lated, occurring  in  urine  in  some  diseases.  The  test  is 
made  by  adding  to  the  urine  solutions  of  sodium  nitrite 
and  sulphanilic  acid  when,  if  the  pathologic  condition 
exists,  a  red  color  is  produced. 

The  reaction  is  also  used  for  the  detection  of  nitrites 
in  water.  In  this  case  the  sulphanilic  acid  and  amido- 
naphthalene are  added  in  acid  solution  to  a  sample  of  the 
water.  If  nitrite  is  present  the  color  is  soon  produced. 
No  reaction  occurs  with  nitrates.  The  test  is  very  deli- 
cate; i  part  of  nitrogen  as  nitrite  in  1,000,000,000  parts  of 
water  can  be  easily  detected,  using  only  about  5  c.c.  of 
the  sample. 

Experiment  64. — Repeat  Experiment  62,  substituting  betamido- 
naphthalene  for  the  alpha-form.  A  pale  yellow  color  will  be 


AZO-,  DIAZO-"  AND  ~HYDRAZO-COMPOUNDS.  183 

developed.  By  the  comparison  of  these  experiments  it  will  be 
seen  that  a  slight  difference  in  arrangement  of  atoms  may  produce 
great  difference  in  properties.  The  two  amidonaphthalenes  are 
close  stereo-isomers,  yet  they  give  markedly  different  azo-deriva- 
tives. 

Experiment  65. — Repeat  Experiment  62,  substituting  for  the 
naphthalene  derivative,  weak  solutions  of  the  following  sub- 
stances: phenol,  aniline,  vanillin,  coumarin,  alphanaphthol,  beta- 
naphthol,  each  as  a  separate  test. 

Experiment  66. — Add  a  few  drops  of  hydrochloric  acid  to 
i  c.c.  of  the  phloroglucol  solution  and  with  this  mixture  make 
tests  of  the  following  substances,  but  touching  them  with  rods 
dipped  in  the  mixture:  cotton,  linen,  fine  writing  paper,  common 
printing  paper  (newspaper).  If  any  of  these  materials  contain 
raw  wood  fiber,  a  bright  red  color  will  be  quickly  developed  at  the 
point  at  which  the  liquid  is  applied.  Common  newspaper  contains 
about  80  per  cent,  ground  wood  and  shows  the  color  strongly. 
Cotton,  linen  and  high-class  writing  paper  being  pure  cellulose  do 
not  give  any  color. 

If  ground  olive  stones,  almond  shells  or  other  materials  contain- 
ing the  so-called  "stone-cells"  be  tested  with  this  solution  the 
color  will  also  be  obtained,  and  by  examining  the  powder  under 
a  power  of  about  100  the  stained  cells  will  show  clearly. 

HYDRAZINS. — In  these  the  nitrogen  atoms  are  united 
by  a  single  bond.  They  are  therefore  structurally  more 
like  the  diamines  than  are  the  azo-derivatives.  The 
important  member  is  phenylhydrazin,  C6H5HN  —  NH2  on 
account  of  its  reactions  with  ketones  and  aldehydes. 

Phenylhydrazin  hydrochloride. — This  substance  is  now 
largely  used  as  a  test  for  sugar.  It  is  a  fawn-colored, 
crystalline  powder  with  an  odor  recalling  that  of  the 
geranium.  It  irritates  the  skin,  producing  in  some  persons 
an  annoying  eruption.  It  is  liable  to  decomposition, 
becoming  dark  and  pasty  and  of  offensive  odor.  It 
should  not  be  used  in  experiments  or  tests  unless  it 
is  in  good  condition.  Phenylhydrazin  hydrochloride 


184  ORGANIC    CHEMISTRY. 

forms  with  ketonic  and  aldehydic  bodies  characteristic 
compounds,  insoluble  in  water,  termed  "osazones"  The 
osazones  are  obtained  in  several  ways.  A  common 
method  is  to  heat  the  carbohydrate,  phenylhydrazin 
compound  and  sodium  acetate  for  some  time  in  boiling 
water  when  the  osazone  separates. 

Dextrose  and  levulose  yield  the  same  osazone,  as  mole- 
cules of  the  hydrazin  group  attach  themselves  to  the  two 
terminal  carbon  atoms  breaking  up,  therefore,  the  alde- 
hydic and  ketonic  structures  which  are,  respectively, 
characteristic  of  the  two  bodies. 

Lactose  and  maltose  yield  osazones;  sucrose  does  not. 

Experiment  67. — Dissolve  0.5  gram  ordinary  glucose  in  10  c.c.  of 
water  in  a  testtube,  add  i  gram  of  sodium  acetate  and  0.5  gram 
of  phenylhydrazin  hydrochloride.  The  proportions  need  not  be 
followed  strictly  but  should  be  approximately  as  given.  The 
phenylhydrazin  should  not  be  allowed  to  come  in  contact  with  the 
skin  as  it  may  irritate  it  severely.  Immerse  the  mixture  in  boiling 
water  for  fifteen  or  twenty  minutes.  A  yellow  crystalline  deposit 
of  phenylglucosazone  will  form.  This  should  be  examined  under 
a  power  of  about  40  or  50  when  the  stellate  crystals  will  be  seen. 

Experiment  68.— Repeat  the  above  experiment  using  the  sub- 
stances separately  and  note  the  differences:  0.5  gram  sucrose; 
0.5  gram  lactose;  0.5  gram  starch.  Only  lactose  forms  a  pre- 
cipitate, but  commercial  sucrose  may  contain  impurities,  and 
yield  a  slight  deposit  of  the  glucosazone. 

Experiment  69. — Test  a  portion  of  the  furfural  distillate,  ob- 
tained in  Experiment  54,  by  heating  it  with  a  few  drops  of  acetic 
acid  and  a  small  amount  of  phenylhydrazin  hydrochloride.  Fur- 
furosazone  will  be  formed. 

If  a  small  quantity  of  phenylhydrazin  hydrochloride  be  added  to 
a  weak  solution  of  formaldehyde,  then  a  few  drops  of  a  fresh  solu- 
tion of  sodium  nitroprusside,  and  then  a  little  sodium  hydroxide 
solution,  a  deep  blue  liquid  is  formed.  This  is  a  delicate  and  use- 
ful test  for  formaldehyde.  With  milk,  the  color  is  greenish. 


ALKALOIDS. 

The  natural  bases  or  alkaloids  are  so  called  because  they 
possess  the  power  of  neutralising  acids,  with  which  they 
form  distinct  and  cry stallis able  compounds.  They  may 
be  divided  into  two  classes:  (T)  Non-volatile  alkaloids 
consisting  of  C,  H,  N  and  O.  These  are  solids,  usually 
crystallisable,  sometimes  possessing  a  definite  melting 
point  and  often  capable  of  sublimation,  though  generally 
with  partial  decomposition.  (2)  Volatile  alkaloids,  con- 
sisting of  C,  H  and  N.  These  are  liquids  capable  of  partial 
vaporisation  at  ordinary  temperatures,  and  usually  having 
very  high  boiling  points.  The  salts  of  the  volatile  alka- 
loids are  non-volatile,  crystallisable  solids. 

The  alkaloids  bear  a  close  resemblance  to  the  sub- 
stitution amines,  but  they  are  more  complex  in  constitu- 
tion, especially  as  regards  the  presence  of  oxygen,  which  is 
not  contained  in  the  common  substitution  amines. 

As  regards  the  general  properties  of  the  non-volatile 
alkaloids,  they  are  solids,  almost  insoluble  in  water  to 
which  they  impart  an  alkaline  reaction.  They  are  usually 
soluble  in  alcohol,  from  which  they  "may  be  readily  crystal- 
lised. They  are  mostly  soluble  in  one  or  more  of  the 
immiscible  solvents,  such  as  chloroform,  ether,  petroleum 
spirit,  benzene  and  amyl  alcohol,  in  which  solvents,  how- 
ever, their  salts  are  insoluble;  the  salts  are  almost  in- 
variably soluble  in  water.  This  difference  in  the  solubili- 
ties of  the  alkaloids  and  their  salts  is  utilised  for  their 
separation  and  purification.  Separation  by  immiscible 

185 


186 


ORGANIC    CHEMISTRY. 


ALKALOIDS. 


187 


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l88  ORGANIC    CHEMISTRY. 

solvents  is  the  basis  of  most  of  the  drug-assay  processes  of 
the  Pharmacopoeia. 

Many  alkaloids  are  bitter,  acrid  or  pungent;  most  of 
them  have  decided  physiological  properties  and  are  the 
proximate  principles  upon  which  the  medicinal  activities 
of  the  plants  containing  them  depend.  A  synopsis  of 
the  formulas,  sources  and  characteristics  of  the  principal 
alkaloids  is  given  on  pages  186,  187. 

The  alkaloids  are  distinguished  from  all  other  plant 
principles  by  the  fact  that  the  aqueous  solutions  of  their 
salts  are  precipitated  by  the  following  reagents :  potassium- 
mercuric  iodide,  iodine,  platinic  chloride,  auric  chloride, 
picric  acid  and  tannin.  They  often  produce  characteris- 
tic color-reactions  with  the  inorganic  acids  and  may  be 
identified  by  the  concurrence  of  several  of  these  tests  which, 
singly,  are  of  little  value. 

The  alkaloids  differ  from  inorganic  bases  in  forming 
salts  by  direct  union  with  the  acid,  not  by  substituting 
the  hydrogen.  Thus,  morphine  forms  with  hydrochloric 
acid  the  compound  C17H19NO3HC1;  it  is,  therefore,  called 
morphine  hydrochlorate  (sometimes  hydrochloride),  not 
morphine  chloride.  This  is  due  to  the  fact  that  the  alka- 
loids are  analogous  to  NH3  rather  than  to  NH4,  and  the 
reaction  between  morphine  and  hydrochloric  acid  is 
similar  to  the  reaction  NH3+  HC1=  NH4C1,  in  which  the 
hydrogen  is  not  replaced;  in  fact,  the  hydrogen  of  the 
acid  may  be  regarded  as  combining  with  the  morphine  to 
form  a  new  molecule,  C17H19NO3H,  analogous  to  ammo- 
nium and  called  morphium]  the  compound  formed  would 
be  morphium  chloride. 

Heroine,  C17H17(C2H3O2)NO3,  is  a  diacetyl  ester  of  mor- 
phine obtained  by  synthesis.  It  is  used  as  a  substitute 
for  morphine. 


ALKALOIDS.  189 

Daturine,  from  stramonium  (Datura  Stramonium),  is  a 
mixture  of  atropine  and  hyoscyamine. 

The  classification  of  the  alkaloids  in  a  group  based  on 
the  property  of  forming  definite  salts  with  acids  brings 
together  compounds  of  very  different  structure.  More- 
over, the  basic  power  differs  considerably  in,  different 
members  of  the  group.  Strychnine,  morphine  and  quinine, 
for  instance,  form  stable  and  definite  compounds.  Caf- 
feine is  a  weak  base,  many  of  its  salts  being  easily  decom- 
posed. 

Several  essentially  different  types  of  molecular  structure 
are  exemplified  in  the  alkaloids. 

Amine  type. — Betaine  is  an  example  of  this  structure. 
Its  sources  and  composition  are  described  under  Pto- 
maines. 

Pyridin  type. — Many  alkaloids  are  of  this  type,  con- 
taining either  the  simple  pyridin  ring  or  the  duplicated 
(quinolin)  ring.  When  either  of  these  is  present,  the 
molecular  structure  is  stable  and  the  substance  resists  the 
action  of  many  reagents. 

Purin  type. — This  is  exemplified  in  caffeine  and  theo- 
bromine.  The  former  is  the  characteristic  alkaloid  of  tea, 
coffee  and  mat6,  and  is  present  in  small  amount  in  cacao; 
the  latter  is  the  principal  alkaloid  of  cacao.  Their  struc- 
tural formulas  are  given  in  connection  with  the  descrip- 
tions of  the  Purins. 

Hydroxyl  and  hydrocarbon  groups  are  often  present. 
The  latter  can  often  be  oxidised  by  mild  oxidising  agents 
to  carboxyl  groups,  thus  converting  the  alkaloids  into 
acids.  Several  alkaloids,  e.  g.,  theophyllin  and  conine, 
have  been  obtained  synthetically.  Isomers  of  quinine 
have  also  been  obtained  synthetically,  but  they  have  not 
the  medicinal  properties  of  the  natural  alkaloid. 


190 


ORGANIC    CHEMISTRY. 


The  annexed  structural  formulas  are  in  some  respects 
provisional  but  they  represent  atomic  arrangements 
suggested  by  the  reactions  and  transformations  of  the 
substances.  It  will  be  seen  that  morphine  contains  the 
phenanthrene  ring  and  no  pyridin.  It  is  more  easily  de- 
composed than  some  other  alkaloids.  Cocaine  and  ber- 
berine  contain  the  benzene  ring;  the  former  contains 
asymmetric  carbon. 

H 
H 
V3H 


H 


HO 


H2C— 
H2C—  N 


Basic  nitrogenous  bodies  occur  in,  and  are  produced  by, 
the  decomposition  of  animal  tissues.  These  are  called 
ptomaines  and  leucomaines  and  are  sometimes  referred  to, 
respectively,  as  the  cadaveric  or  animal  alkaloids.  They 
are  described  below. 


ALKALOIDS.  igi 

Many  artificial  alkaloids  or  allied  compounds  have 
attained  prominence  in  therapeutics  during  recent  years. 
Some  of  these  possess  the  specific  power  of  reducing  the 
animal  temperature,  and  are  collectively  known  as 
antipyretics.  They  are  sometimes  called  the  "coal-tar 
synthetics"  in  recognition  of  their  origin.  They  are 
generally  known  by  trade-names  which  may  be  either 
abbreviations  of  their  systematic  names  or  purely  arbi- 
trary. The  following  are  the  more  important  of  these: 

Acetanilid,  antifebrin,  C6H5NH(C2H3O).— This  is  ob- 
tained by  the  reaction  of  aniline  with  acetic  anhydride. 
It  forms  colorless  and  odorless  crystals,  soluble  in  200  parts 
of  cold  water,  much  more  freely  in  boiling  water,  alcohol, 
ether  and  chloroform.  It  is  used  as  an  antiseptic  dressing 
and  internally  as  an  antipyretic.  It  is  the  basis  of  several 
proprietary  antipyretics  and  is  usually  present  in  so- 
called  "headache  powders." 

Antipyrin,  phenazone,  phenyldimethylpyrazolon,  CUH12- 
N2O. — This  is  prepared  by  the  action  of  phenylhydrazin 
on  ethyl  acetoacetate.  It  forms  colorless  crystals,  freely 
soluble  in  water,  alcohol  and  chloroform. 

Phenacetin,  acetphenetidin,  C6H4(NHCH3CO)OC6H5.— 
This  is  prepared  by  the  action  of  glacial  acetic  acid  on 
paraphenetidin.  It  forms  colorless  crystals  slightly  sol- 
uble in  cold  water,  alcohol,  ether  and  chloroform. 


ORGANIC    CHEMISTRY. 


O 

— C— CH3 
I 
CH, 

Methyl  acetanilid  Phenacetin 

(Exalgin) 

Experiment  70. — Dissolve  o.i  gram  of  quinine  sulphate  in  10 
c.c.  of  water.  Add  two  drops  of  bromine  water  and  afterward  an 
excess  of  ammonium  hydroxide.  The  liquid  will  assume  a  bright 
emerald-green  color.  This  is  known  as  the  thalleioquin  reaction 
and  will  also  be  given  by  quinidine  or  its  salts. 

Experiment  71. — Dissolve  .02  gram  of  morphine  sulphate  in 
2  c.c.  of  water  and  add  several  drops  of  solution  of  ferric  chloride. 
A  blue  color  will  be  produced  which  is  destroyed  by  heating. 

Experiment  72. — Add  a  small  quantity  of  morphine  or  one  of 
its  salts  to  a  drop  of  nitric  acid  upon  a  porcelain  surface.  An 
orange-red  color  will  be  produced  which  rapidly  fades. 

Experiment  73. — Dissolve  .01  gram  of  strychnine  in  about  5  c.c. 
of  water  and  transfer  the  solution  to  a  small  separatory  funnel. 
Add  about  2  c.c.  of  chloroform  and  then  render  the  aqueous  liquid 
alkaline  with  sodium  carbonate.  Upon  shaking  the  separatory 
funnel  the  liberated  alkaloid  enters  into  solution  in  the  chloroform, 
which  may  be  drawn  off,  evaporated,  and  the  residue  tested  as 
under  Experiment  74. 

Experiment  74. — Dissolve  a  minute  quantity  of  strychnine,  or 
one  of  its  salts,  in  a  few  drops  of  concentrated  sulphuric  acid  on 
a  white  porcelain  or  glass  surface,  and  add  a  small  crystal  of  potas- 
sium dichromate.  Upon  stirring  the  crystal  of  dichromate  around 
with  a  glass  rod  a  blue  color  will  be  at  first  produced,  which  changes 
to  purplish  blue  and  gradually  fades  through  red  to  yellow.  Ceroso- 
ceric  oxide,  manganese  dioxide  or  similar  oxidising  agents  will 
produce  the  same  effect  as  potassium  dichromate. 

Experiment  75. — Rub  together  4  parts  of  hydrastine  and  i  part 
of  morphine  and  treat  a  minute  quantity  as  in  Experiment  74.  A 


PTOMAINES    AND    LEUCOMAINES.  193 

color  similar  to  the  strychnine  will  be  produced,  which  does  not 
fade  out  as  rapidly  but  is  more  permanent.  Tests  with  morphine 
and  hydrastine  separately  will  fail  to  show  any  color. 

Experiment  76. — Heat  a  small  quantity  of  atropine  with  several 
c.c.  of  sulphuric  acid.  A  peculiar  aromatic  odor  is  evolved  re- 
calling a  mixture  of  rose  and  orange  flower.  Add  a  small  frag- 
ment of  potassium  dichromate  and  the  odor  will  change  to  that  of 
bitter  almond  oil. 

Experiment  77. — Add  a  small  amount  of  colchicine  to  a  drop  of 
nitric  acid  on  a  white  porcelain  or  glass  surface.  A  blue  color  will 
be  produced  which  fades  in  a  short  time. 

Experiment  78. — Rub  a  small  quantity  of  veratrine  with  a  few 
drops  of  sulphuric  acid  on  a  white  porcelain  or  glass  surface  and 
observe  the  intense  red  color  which  is  produced,  which  does  not 
fade  even  after  several  hours. 

Experiment  79. — Dissolve  a  small  quantity  of  caffeine  in  a  few 
drops  of  hydrochloric  acid,  add  a  few  small  crystals  of  potassium 
chlorate  and  heat  over  a  water  bath  until  a  dry  residue  remains. 
Expose  the  residue  to  the  vapor  of  ammonium  hydroxide  and 
observe  the  characteristic  rich  purple  color  which  it  assumes. 
This  is  known  as  the  murexid  test.  Uric  acid  will  give  the  same 
reaction,  being  closely  analogous  in  structure  to  caffeine. 


PTOMAINES  AND  LEUCOMAINES. 

The  chemical  changes  classed  under  the  terms  fermen- 
tation and  putrefaction  are  caused  by  living  organisms, 
mostly  very  minute,  and  included  under  the  general  title 
"microbes."  It  seems  probable  that  all  such  transfor- 
mations are  due  to  enzyms.  The  principal  action  is  the 
breaking  down  of  complex  nitrogenous  ingredients  of  the 
living  tissues,  often  by  hydrolysis,  but  also  by  other  types 
of  action,  especially  oxidation  when  the  action  occurs  in  the 
presence  of  air.  It  follows,  therefore,  that  if  air  be  ex- 
cluded, the  chemical  changes  will  be  somewhat  different, 
and  hence  a  distinction  is  made  between  the  usual  (aerobic) 
decompositions  and  those  that  occur  out  of  contact  with 
13 


194  ORGANIC    CHEMISTRY. 

free  oxygen  (anaerobic).  The  latter  class  has  not  been  as 
yet  extensively  studied. 

The  products  of  aerobic  fermentation  and  putrefaction 
have  been  of  late  studied  with  great  zeal.  Many  of  them 
are  distinctly  basic  resembling  the  alkaloids.  Further- 
more, the  normal  pathologic  processes  of  animals  give  rise 
to  basic  bodies.  It  is  hardly  necessary  to  distinguish 
these  different  classes,  but  such  distinction  has  been  made. 
The  basic  bodies  produced  by  microbes  are  called  "pto- 
maines," those  produced  in  animals,  "leucomaines" 
The  latter  term  is  not  much  used.  Care  must  be  taken 
not  to  confuse  the  products  of  animal  tissues  (leucomaines) 
with  the  products  of  microbes  inhabiting  the  tissues, 
fluids  or  cavities  of  animals.  The  latter  are  ptomaines, 
for  they  are  the  result  of  fermentation  or  putrefaction 
apart  from  the  vital  action  of  the  animal.  As  such  result- 
ing bodies  cause  disease  by  absorption  into  the  fluids  of  the 
animal  they  are  sometimes  termed  ''toxins."  By  special 
methods,  bodies  (antitoxins)  antagonistic  in  physiologic 
effect  can  be  obtained  and  used  in  the  treatment  of  diseases 
caused  by  toxins. 

Microorganisms  either  directly  or  by  intermediate  action 
of  enzyms,  may  produce  alcohols,  acids,  neutral  substances, 
cyclic  compounds  and  nitrogenous  derivatives;  in  fact, 
representatives  of  any  class  of  organic  compounds.  The 
term  ptomaine  is  derived  from  a  Greek  word  meaning  a 
dead  body,  and  following  out  the  analogy  we  might  apply 
the  same  term  to  all  the  products  of  the  decomposition  of 
organic  bodies  under  the  influence  of  microorganisms, 
distinguishing  the  different  classes  by  the  proper  ter- 
minations. Thus  ptomols  would  be  alcohols,  produced 
by  such  action.  Lactic  and  butyric  acids  are  ordinarily 
produced  by  the  action  of  microbes  and  are  therefore 
ptomic  acids. 


PTOMAINES    AND    LEUCOMAINES.  195 

It  is  to  be  noted,  therefore,  that  the  ptomaines  are 
not  peculiar  as  a  class  among  basic  organic  bodies,  nor 
are  they  the  only  products  of  decompositions. 

All  ptomaines  contain  nitrogen,  but  the  relation  of 
this  to  the  other  atoms  is  dependent  on  the  nature  of  the 
original  molecule  and  the  microbes  or  enzyms  which 
bring  about  the  transformation.  Of  the  different  types 
of  combination  that  nitrogen  may  exhibit,  amido-,  azo-  and 
diazo-groups  are  the  most  common.  Pyridin  compounds 
are  not  usual  among  the  products  of  ordinary  putrefaction ; 
nitro-  and  nitroso-groupings  are  never  observed. 

The  amines  observed  range  in  complexity  from  true 
basic  monamines  to  tetramides  with  acid  function. 

Of  the  simpler  type  are  some  common  ptomaines,  such 
as  putrescine,  N2H4(CH2)4,  tetramethene  diamine,  and 
cadaverine,  (NH2)(CH2)5,  pentamethenedia'mine.  A  syn- 
thetic product  used  in  medicine  is  also  of  analogous  struc- 
ture, piperazin,  diethenediamine,  N2H4(C2H4)2.  Similar 
but  more  complicated  bodies  are  indicated  in  the  annexed 
structural  formulas.  They  are  of  the  general  type  of  the 
true  bases  and  it  will  be  seen  that  alcoholic  and  acid 
groupings  are  also  represented. 

H3C     H    H  H3C    H    H 

N 

Li  I         I         I  -n-s  I 

O    H    H  O 

i.;:         ::i 

Choline  Neurine 

Choline. — Salts  of  this  base  occur  in  many  animal  and 
vegetable  tissues.  It  was  originally  extracted  from  bile 


196  ORGANIC    CHEMISTRY. 

to  which  the  name  refers.  Its  glycerophosphate  exists  in 
lecithins.  As  will  be  seen  from  the  structural  formula 
it  is  a  complex  derivative  of  ammonium  hydroxide.  It  is 
strongly  alkaline,  absorbing  water  and  carbon  dioxide 
from  the  air.  It  forms  a  crystalline  chloroplatinate. 

Neurine. — This  is  obtained  by  boiling  choline  with 
barium  hydroxide  and  is  produced  in  some  putrefactions. 

Muscarine  occurs  associated  with  choline  in  poisonous 
mushrooms. 

Betaine  occurs  in  the  sugar  beet  and  is  also  produced 
by  the  cautious  oxidation  of  choline. 

H3C     H     H  H3C 

— C— C— O— H      | 

I  Ais^- 

*  HAH 

H     H 

Muscarine  Betaine 

PURINS. — Alloocuric  bodies,  Xanthin  bases. — Under  these 
terms,  the  first  being  now  much  in  vogue,  is  included  a 
number  of  bodies  of  complex  structure  which  it  has  been 
proposed  to  regard  as  derived  from  a  hypothetical  radicle 
termed  the  "purin  nucleus."  From  this,  by  association 
with  other  radicles,  such  as  amidogen,  imidogen,  hydroxyl 
and  carbonyl,  formulas  of  the  members  of  the  series  may 
be  obtained.  The  following  formulas  show  the  relations 
of  some  of  the  members  of  the  series  to  the  purin  nucleus 
and  to  purin  itself: 

N=C—  N=CH 

— C     C— N  HC      C-NH 

II      II        \  II  \ 

N_C-N=C  N-C— N=C 

Purin  nucleus  Purin 


PTOMAINES    AND    LEUCOMAINES.  IQ7 

It  will  be  seen  that  purin  is,  in  a  measure,  a  duplicated 
urea,  the  oxygen  being  absent  and  part  of  the  hydrogen 
replaced  by  carbon.  The  purin  bodies  are  at  present 
attracting  much  attention  owing  to  their  supposed  relation 
to  animal  nutrition  and  metabolism.  They  exist  in 
many  foods  and  abundantly  in  tea,  coffee,  mate  and  cacao. 

The  following  table  gives  the  empirical  formulas  of 
some  members  of  this  group,  and  a  few  structural  for- 
mulas are  annexed: 

Uric  acid C5H4N4O3 

Xanthin   C5H4N4O2 

Hypoxanthin C5H4N4O 

Paraxanthin    C7H8N4O2 


Theobromine   C7H8N4O2 

Caffeine C8H10N4O2 

Adenine Q>H5N5 

H— N— C— H  H3C— N— C— H 

I      II  I      II 

0  =  C     C— N— H  0  =  C     C— N— CH3 

I       I         \  I       I         \ 

H— N— C=N— C  H— N— C=N— C 

II  II 

o  o 

Xanthin  Theobromine 

H— N— C=O  H3C— N— C— H 

II  I      II 

0  =  C     C— N— H  O=C     C— N— CH3 

I      II        \  I       I         \ 

H— N— C— N— C=0     H3C— N— C=N— C=O 

A 

Uric  acid  Caffeine 


IQ8  ORGANIC    CHEMISTRY. 

Of  these  bodies  caffeine  and  theobromine  are  described 
in  connection  with  the  group  of  alkaloids  in  which  they 
are  usually  classified,  but  they  possess  only  feebly  basic 
properties,  and  their  formulas  are  structurally  very 
different  from  those  in  the  majority  of  that  group. 

Uric  acid,  trioxypurin,  C5H4N4O3. — This  occurs  in  small 
amount  in  the  urine  of  mammals  and  abundantly  in  that 
of  birds  and  reptiles.  It  can  be  obtained  by  strongly 
acidulating  urine  with  hydrochloric  acid  and  allowing  the 
mixture  to  stand  for  some  hours.  Uric  acid  separates 
as  a  crystalline  precipitate,  usually  brownish,  from  ad- 
herent coloring  matter.  When  pure  it  is  in  colorless 
crystals,  almost  insoluble  in  cold  water  and  only  slightly 
soluble  in  boiling  water.  It  forms  several  derivatives  with 
sodium,  potassium  and  ammonium, usually  called  ' '  urates, ' ' 
which  are  more  soluble  in  water  than  the  acid  itself. 
Uric  acid  does  not  contain  the  carboxyl  radicle,  but  the 
group  HNCO,  which  occurs  thrice  in  the  molecule,  confers 
nominal  acidity. 

Xanthin,  dioxypurin,  C5H4N4O2. — This  occurs  in  small 
amount  in  urine,  but  is  more  abundant  in  flesh  juice,  hence 
is  found  in  commercial  meat-extract.  It  is  colorless, 
crystalline  and  nearly  insoluble  in  cold  water.  It  is 
dissolved  by  alkaline  solutions. 

Hypoxanthin,  oxypurin,  C5H4N4O2. — This  is  found  as- 
sociated with  xanthin.  It  is  crystalline  and  but  slightly 
soluble  in  cold  water. 

Paraxanthin,  dimethylxanthin,  C7H8N4O2,  is  isomeric 
with  theobromine. 

Adenine,  amidopurin,  C5H5N5. — This  occurs  in  several 
animal  fluids,  but  is  most  abundant  in  tea-leaves.  It 
contains  no  oxygen. 

Purin  bodies  are  without  nutritive  value  to  the  higher 


PTOMAINES    AND    LEUCOMAINES.  IQQ 

animals,  hence  any  that  are  present  in  the  food  are  passed 
off  as  promptly  as  possible  by  the  excretions.  The  or- 
dinary waste  of  tissue  (destructive  metabolism)  in  the 
animal  produces  purins,  hence  the  excretions  will  contain 
both  those  in  the  food  and  those  formed  in  the  body.  The 
former  are  termed  ''exogenous  purins,"  the  latter  "en- 
dogenous purins." 

Many  analyses  of  food  stuffs  have  been  made  in  order- 
to  determine  the  amount  of  purins,  so  that  the  diet  may  be 
regulated  to  secure  the  minimum  amount  of  exogenous 
purins  when  these  are  especially  objectionable.  Meats, 
some  wines  and  cereals  contain  considerable  amounts  of 
purins;  milk,  eggs  and  cheese  small  amounts.  Compara- 
tively few  natural  purins  have  been  isolated,  but  over  one 
hundred  derivatives  have  been  prepared  synthetically. 

The  endogenous  purins  are  regarded  as  derived  largely 
from  the  nucleoproteids  by  successive  dissociation,  with 
probably  both  hydrolysis  and  oxidation  under  the  influ- 
ence of  enzyms.  If  these  processes  be  carried  to  a  con- 
siderable extent,  as  occurs  when  the  functions  of  nutrition 
and  excretion  are  well  balanced,  the  purin  derivatives  are 
mostly  converted  into  a  simple  diamido-compound  urea, 
which  constitutes  the  principal  result  of  the  waste  of 
nitrogenous  tissues  in  the  higher  animals  and  is  the  most 
abundant  solid  ingredient  of  normal  human  urine. 

Urea  and  some  closely  related  excretory  substances  are 
described  elsewhere. 


PROTEIDS  OR  ALBUMINOIDS. 

Proteids  or  albuminoids  are  complex  bodies  that  form 
the  essential  portions  of  living  tissues.  They  all  contain 
hydrogen,  oxygen  and  nitrogen;  most  of  them  contain 
also  sulphur;  a  few  contain  phosphorus,  and  a  few  con- 
tain iron.  Even  copper  has  been  found  in  some,  and  it  is 
not  unlikely  that  elements,  not  usually  existing  in  natural 
organic  bodies,  are  present  in  proteids  having  highly 
specialised  function  or  developed  under  exceptional  con- 
ditions. 

Little  is  known  as  to  the  structural  formulas  of  proteids, 
except  that  they  are  all  very  complex,  containing  open  and 
closed  carbon  chains.  The  nitrogen  is  probably  in  a 
pyridin  ring  and  partly  in  a  cyanogen  or  amine  form. 
Some  authorities  distinguish  between  proteids  and  al- 
buminoids, limiting  the  latter  term  to  gelatin  and  closely 
analogous  bodies.  Other  authorities  limit  the  term 
proteid  to  substances  that  yield  monamido-acids  on  de- 
composition by  certain  processes.  These  distinctions, 
however,  can  not  be  regarded  as  final,  and  it  is  sufficient 
for  present  study  to  classify  a  considerable  number  of 
bodies  under  the  general  terms  here  used,  even  though 
appreciable  differences  in  properties  are  noted.  The 
proper  classification  will  be  made  when  the  rational 
formulas  become  known. 

Proteids  are  generally  colorless  or  faintly  yellow  amor- 
phous solids,  soluble  in  water,  but  some  require  for  this 
purpose  the  coincident  presence  of  certain  salts.  Some 
proteids  dissolve  in  alcohol.  Water  solutions  putrefy 


PROTEIDS    OR    ALBUMINOIDS.  2OI 

promptly,  under  ordinary  conditions,  but  this  is  merely 
the  result  of  the  action  of  microbes.  In  the  presence 
of  antiseptics  or  in  sterile  solution  proteids  are  practically 
permanent.  They  are  ordinarily  eminently  colloid,  hence 
have  very  low  diffusive  power,  but  one  proteid  .has  been 
obtained  in  a  distinctly  crystalline  form,  and  there  is  no 
reason  to  doubt  that  all  of  them  are  capable  of  crystal- 
lising under  certain  conditions.  Solutions  of  proteids  have 
marked  levorotatory  power, 

A  satisfactory  classification  of  proteids  is  impossible 
in  the  present  imperfect  state  of  knowledge.  In  many 
cases  several  bodies  are  probably  included  under  one  name ; 
in  other  cases  a  supposed  natural  proteid  is  a  product 
of  the  methods  employed  in  obtaining  it.  The  classi- 
fications usually  followed  take  but  little  account  of  vege- 
table proteids,  although  these  are  quite  numerous.  The 
following  classification  is  that  of  Hammarsten;  it  is  merely 
an  incomplete  index  to  the  animal  proteids. 

Simple  proteids  or  albumins: 

Albumins  proper:  Ovalbumin,  seralbumin,  lactalbumin. 

Globulins:  Fibrinogen,  vitellin,  myosin,  crystallin. 

Nucleoalbumin :  Casein. 

Albuminates :  Acid  albuminate,  alkali  albuminate. 

Albumoses. 

Peptones. 

Coagulated  proteids:  Fibrin,  coagulated  albumins. 

Compound  proteids : 

Hemoglobins. 

Glyco-proteids :  Mucins,  hyalogens,  amyloid. 
Nucleoproteids :  Nucleohiston,  cytoglobin. 
Albuminoids:  Keratin,  elastin,  collagen. 

Many  proteids  are  precipitated  from  their  solution  in 
water,  in  forms  that  are  not  capable  of  re-solution  without 
chemical  change.  This,  which  is  termed  "coagulation," 


202  ORGANIC    CHEMISTRY. 

is  brought  about  by  heat  in  some  cases,  by  different  chem- 
ical agents  in  others;  each  proteid  requiring  particular 
methods.  When  quite  dry,  proteids  show  little  tendency 
to  change.  By  strong  heating  they  are  converted  in  a 
mixture  of  substances,  among  which  pyridin  and  some 
of  its  derivatives  are  especially  noticeable. 

Coagulated  Proteids. — Under  this  term  are  included 
proteids  rendered  insoluble  in  their  normal  solvents,  pure 
water  or  saline  solutions,  as  the  case  may  be.  In  some 
cases  they  may  be  identical  with  the  original  body,  but 
in  most  cases  they  are  probably  modified  either  by  hydroly- 
sis or.  oxidation  with  or  without  division  into  two  or  more 
new  substances.  Most  of  them  can  be  converted  into 
proteoses  and  finally  into  peptones  by  the  action  of  some 
enzyms,  and  on  this  fact  depends  the  digestibility  of  many 
articles  that  are  prepared  by  cooking,  by  which  the  pro- 
teids are  coagulated. 

ALBUMINS  PROPER. — This  group,  includes  ovalbumin 
(egg  albumin),  ser  albumin  (blood  albumin)  and  lactalbumin 
(milk  albumin).  Care  must  be  taken  not  to  confuse 
''albumin"  with  "albumen."  The  latter  term  refers  to 
the  nutritive  material  surrounding  an  embryo.  It  con- 
tains one  or  more  proteids  which  may  or  may  not  be 
albumins.  White  of  egg  is  the  "albumen"  of  the  egg. 
It  contains  ovalbumin,  water  and  other  bodies.  The 
seeds  of  many  plants  contain  a  large  amount  of  material 
around  the  embryo.  This  is  called  the  "albumen"  of  the 
seed.  In  the  common  cereals  this  albumen  contains 
several  proteids,  with  much  starch  and  some  fatty  matter 
and  salts. 

The  albumins  are  soluble  in  water  and  in  weak  saline 
solutions.  In  strong  saline  solution  they  are  coagulated 
at  a  temperature  of  about  60°.  Alkalies  and  very  small 
amounts  of  acids  do  not  precipitate  them,  but  larger 


PROTEIDS     OR    ALBUMINOIDS.  203 

amounts  do,  as  also  many  neutral  salts,  among  which  are 
ammonium  sulphate  and  mercuric  chloride. 

GLOBULINS. — Globulins  are  insoluble  in  water,  but 
soluble  in  dilute  solutions  of  sodium  chloride.  They  are 
precipitated  unchanged  from  these  solutions  by  dilution 
with  pure  water. 

Vitellin  is  obtained  from  egg-yolk;  it  resembles  some- 
what the  nucleoalbumins.  It  has  not  been  obtained  free 
from  lecithin. 

Crystallin  is  obtained  from  the  crystalline  lens. 

Fibrinogen. — This  exists  in  blood  plasma.  When  blood 
clots,  the  fibrinogen  is  converted  into  fibrin,  which  forms 
the  clot  and  encloses  the  blood  corpuscles.  This  coagu- 
lation occurs  under  the  influence  of  another  substance, 
termed  "fibrin-ferment,"  or  "thrombin"  which  also 
exists  in  the  blood  plasma.  The  nature  of  thrombin  is 
not  known,  but  it  is  probably  an  enzym. 

Myosin  is  obtained  from  muscles.  According  to  some 
authorities,  the  fluids  in  living  muscles  contain  a  proteid 
termed  myosinogen  which  is  converted  after  the  death  of 
the  tissue,  when  the  stiffening  (rigor  mortis)  sets  in,  into 
myosin. 

NUCLEOALBUMINS. — These  are  distinguished  from  most 
other  proteids  by  containing  notable  amounts  of  phospho- 
rus. The  most  important  is  casein,  the  principal  portion 
of  the  fresh  curd  of  cow's  milk.  Some  authorities  apply 
the  term  " caseinogen"  to  the  material  as  it  exists  in  milk, 
and  the  term  "casein"  to  the  separated  proteid.  In  fresh 
milk  the  casein  (caseinogen)  exists  in  association  with  some 
calcium  phosphate  and  is  probably  partly  in  a  jelly-like 
condition,  not  in  true  solution.  Most  acids,  many  mineral 
salts,  and  several  enzyms  coagulate  milk,  but  much  pro- 
teid remains  in  solution,  and  it  is  probable  that  hydrolysis 


204  ORGANIC    CHEMISTRY. 

occurs,  and  the  original  proteids  are  split  into  several 
substances  some  of  which  precipitate  and  others  remain 
dissolved.  A  solution  of  mercuric  nitrate  in  excess  of 
nitric  acid  precipitates  all  the  proteids  of  cows'  milk. 

Cheese  is  proteid  matter  obtained  from  milk  either  by 
the  action  of  acids  or  by  rennet,  a  preparation  of  enzyms 
from  the  stomach  of  the  calf.  The  acid  usually  employed 
is  lactic,  the  result  of  the  natural  souring  of  milk  by  fer- 
mentation of  milk  sugar.  Cheese,  even  when  fresh,  does 
not  contain  the  same  proteids  as  milk,  and  in  ripe  cheese 
further  changes  have  occurred  through  the  action  of 
microbes  and  enzyms,  by  which  amine  bodies  have  been 
produced.  Ammonium  compounds  are  present  in  well- 
ripened  cheese.  Sometimes  ptomaines,  either  amine 
derivatives  or  azo-compounds  are  present,  thus  making 
the  cheese  poisonous. 

ACID-ALBUMINATES     AND     ALKALI-ALBUMINATES. Many 

proteids  combine  to  a  limited  extent  with  acids  or  with 
alkalies,  producing  compounds  that  have  characteristic 
properties.  The  exact  nature  of  the  combination  is  not 
known.  By  the  action  of  somewhat  strong  solutions  of 
alkali  on  natural  proteids,  chemical  changes  are  produced 
in  the  latter,  among  which  are  the  elimination  of  nitrogen 
and  sulphur.  By  dissolving  proteids  in  hydrochloric  acid, 
acid-albuminates  may  be  obtained.  Both  these  products 
have  certain  properties  in  common.  *  They  are  nearly 
insoluble  in  water  and  dilute  solution  of  sodium  chloride, 
but  are  dissolved  by  water  on  the  addition  of  a  little  acid 
or  alkali.  The  solution  is  not  coagulated  by  heat,  but  can 
be  precipitated  without  heat  by  neutralising  the  solvent 
substance,  that  is,  adding  acid  to  the  alkali-albumin  and 
alkali  to  the  acid-albumin.  Strong  mineral  acids  pre- 
cipitate both  classes  of  albuminates. 


PROTEIDS    OR    ALBUMINOIDS.  205 

Syntonin  is  an  acid-albuminate  obtained  by  the  action 
of  acids  on  myosin. 

Albumoses  and  Peptones. — The  action  of  hydrolysing 
enzyms,  such  as  those  in  the  gastric  juice  and  pancreatic 
secretions  on  proteids,  results  finally  in  the  formation  of  a 
substance  or  mixture  of  substances,  similar  to  the  common 
proteids  in  many  ways  but  much  more  diffusible  and  much 
less  coagulable.  This  is  called  peptone.  In  the  course  of 
its  formation  from  the  original  proteid,  several  inter- 
mediate transformations  occur,  the  products  of  which  are, 
collectively,  called  proteases  or  albumoses.  These  products 
differ  with  the  conditions  of  action  and  the  proteid  and 
enzym,  and  much  remains  to  be  determined  in  regard  to 
them.  At  present  it  is  the  custom  to  consider  all  the 
proteid  matter  that  is  not  precipitated  by  saturated  solu- 
tion of  ammonium  sulphate,  as  peptone;  that  which  is  so 
precipitated  as  either  unaltered  proteid  or  some  form  of 
proteose. 

HEMOGLOBIN. — This  is  the  coloring  matter  of  blood-cor- 
puscles. It  is  distinguished  from  many  other  proteids  by 
containing  iron,  which  is  part  of  the  molecule  and  not,  as 
with  some  proteids,  merely  due  to  adherent  mineral 
matter.  Chlorophyl,  the  green  coloring  matter  of  plants 
also  contains  iron,  and  its  functions  are  analogous  to  those 
of  hemoglobin.  In  some  animals  the  iron  in  hemoglobin  is 
partly  or  wholly  replaced  by  copper. 

Hemoglobin  is  very  soluble  in  water,  producing  a  red 
solution  that  shows  characteristic  absorption  bands.  '  It 
can  be  obtained  in  a  crystalline  form.  Its  principal 
property  is  the  power  to  take  up  oxygen  and  to  give  this 
up  again  under  the  influence  of  different  substances.  The 
oxygen  compound  differs  slightly  in  composition  according 
to  the  pressure  of  the  gas  from  which  the  absorption  takes 


206  ORGANIC    CHEMISTRY. 

place.  As  a  rule,  hemoglobin  absorbs  only  free  oxygen. 
It  has  affinity  for  other  bodies,  such  as  nitrous  oxide,  nitric 
oxide,  hydrogen  sulphide,  carbon  monoxide,  carbon  dioxide 
and  acetylene.  The  affinity  for  carbon  monoxide  and  nitric 
oxide  is  stronger  than  the  affinity  for  most  of  the  other 
substances.  All  these  derivatives  of  hemoglobin  give 
characteristic  absorption  bands.  By  exposing  oxyhemo- 
globin  for  some  time  to  the  action  of  free  oxygen  or  to  mild 
oxidising  agents,  a  substance  known  as  methemoglobin  is 
formed.  It  is  believed  that  in  this  the  oxygen  is  more 
strongly  combined  than  is  the  case  with  oxy hemoglobin. 
The  associated  oxygen  of  oxyhemoglobin  can  be  driven 
out  by  reducing  the  pressure  or  by  passing  through  a 
current  of  nitrogen  or  any  of  the  bodies  mentioned  above 
as  forming  compounds  with  it. 

Hematin  is  obtained  by  the  action  of  alkalies  or  acids 
on  hemoglobin.  Its  composition  approximates  the  for- 
mula C32H32N4FeO4.  Hematin  heated  to  about  80°  with 
glacial  acetic  acid  and  a  little  sodium  chloride,  yields 
a  chlorine  derivative  termed  hemin.  It  is  regarded  as  a 
hydrochloric  ester  of  hematin.  It  forms  characteristic 
crystals,  sometimes  termed  Teichmann's  crystals.  The 
reaction  is  one  of  the  standard  tests  for  blood. 

Oxyhemoglobin  gives  with  a  mixture  of  guaiacum  tinc- 
ture and  hydrogen  dioxide  a  blue  solution,  the  production 
of  which  is  also  a  test  for  blood. 

MUCIN. — Under  this  term  several  proteids  are  included. 
They  are  found  in  the  secretion  of  mucous  membranes,  in 
connective  tissue,  tendons  and  the  submaxillary  gland. 
Proteid  matter  that  coagulates  with  nitric  acid,  frequently 
appears  in  urine.  It  is  also  termed  mucin,  but  many 
authorities  regard  it  as  essentially  different  from  true 
mucin,  and  properly  a  nucleoalbumin.  True  mucin  may, 


PROTEIDS    OR    ALBUMINOIDS.  207 

however,  be  present  in  urine  containing  a  large  amount  of 
mucus.  By  the  action  of  acids,  mucin  can  be  hydrolysed 
and  a  reducing  carbohydrate  formed. 

NUCLEINS. — These  are  a  series  of  bodies  containing 
notable  amounts  of  phosphorus.  They  are  widely  dis- 
tributed in  the  vegetable  and  animal  kingdom,  and  have 
been  classified  in  two  groups:  Nucleins  proper,  which 
yield  proteids,  phosphoric  acid  and  xanthin  bases;  and 
pseudonucleins  that  yield  no  xanthin  bases.  The  true 
nucleins  are  obtained  as  insoluble  residues  in  the  digestion 
of  nucleoproteids  by  gastric  juice.  By  the  action  of 
alkalies,  nucleates  are  formed,  from  which  nucleic  acids  may 
be  obtained.  All  nucleins,  by  boiling  with  dilute  acids, 
yield  a  series  of  nitrogenous  bodies  termed  the  xanthin  or 
nuclein  bases.  They  have  close  structural  relations  to 
some  alkaloids,  leucomaines  and  uric  acid.  It  has  been 
suggested  that  they  are  all  derived  from  a  body  having 
the  formula  C5H4N4  to  which  the  name  purin  has  been 
applied.  Hence  the  group  is  often  called  the  "  purin 
bases."  (See  Purins.) 

KERATIN  is  the  chief  proteid  constituent  of  horny  struc- 
tures, hair  and  nails.  Some  of  its  reactions  are  similar 
to  those  of  the  proteids  proper,  but  it  is  not  digested  by 
gastric  or  pancreatic  secretions. 

ELASTIN  occurs  in  connective  tissue,  especially  the  cer- 
vical ligament.  It  is  insoluble  in  water,  and  dissolves 
only  slowly  in  alkalies  and  acids. 

COLLAGEN  is  the  material  in  connective  tissue  and  bone 
from  which  gelatin  is  obtained.  GELATIN  is  prepared  by 
boiling  the  tissue  with  water.  The  process  is  very  slow 
at  ordinary  pressure,  but  in  a  closed  vessel,  the  tempera- 
ture can  be  raised  considerably  and  the  gelatin  rapidly 
produced.  The  change  is  doubtless  a  hydrolysis. 


208  ORGANIC    CHEMISTRY. 

The  food  material  called  isinglass  is  probably  a  collagen 
that  is  easily  converted  into  gelatin.  Ordinary  gelatin 
dissolves  in  hot  water,  and  the  solution  on  cooling  sets  to  a 
jelly  if  considerable  of  the  gelatin  is  present.  Solutions 
of  gelatin  are  promptly  precipitated  by  tannins,  common 
tannins.  The  tanning  of  skins  is  dependent  on  the  reac- 
tion by  which  the  albuminoids  are  rendered  insoluble  and 
non-putrescent.  This  was  originally  carried  out  by  the 
use  of  tannins,  but  several  other  methods  are  now  in  use. 
Formaldehyde  converts  gelatin  into  a  mass  insoluble  in 
water. 

VEGETABLE  PROTEIDS. — As  a  purely  vegetable  diet  will 
support  life  satisfactorily  for  a  long  period,  it  is  reasonable 
to  suppose  that  the  vegetable  proteids  are  of  the  same 
general  character  as  the  animal  proteids,  but  the  isolation 
and  classification  of  the  former  are  as  yet  very  incomplete. 
Recently,  careful  investigations  have  been  made  into  the 
proteids  of  important  cereals.  The  principal  proteids  of 
wheat  flour  are  gliadin  and  glutenin.  The  former,  which 
constitutes  nearly  half  the  proteid  matter  of  the  grain, 
is  soluble  in  pure  water  and  in  dilute  alcohol,  but  almost 
insoluble  in  water  containing  the  mineral  matters  of  the 
wheat -grain.  Glutenin  is  insoluble  in  water,  dilute  saline 
solutions  and  dilute  alcohol.  The  glutinous  property  of 
wheat  flour  is  due  to  both  the  proteids,  the  gliadin  giving 
the  adhesiveness  and  glutenin  the  solidity. 

LECITHINS. — These  are  complex  bodies  that  occur  in  the 
protoplasm  of  many  forms  of  cells,  either  alone  or  in  com- 
bination, or  close  association,  with  proteids.  A  lecithin  is 
an  ester  derived  from  glycerophosphoric  acid  by  sub- 
stitution of  two  of  the  hydrogen  atoms  of  the  latter  by  two 
molecules  of  radicles  of  the  fatty-acids  and  the  other 
hydrogen  atom  by  a  base  "  choline."  Since  the  substitut- 


PROTEIDS    OR    ALBUMINOIDS. 


209 


ing  radicles  may  differ,  a  considerable  number  of  bodies 
of  the  same  type  may  be  produced.  The  annexed  struc- 
tural formulas  show  glycerophosphoric  acid  and  one  of  the 
common  lecithins. 


H 

4 


H  H 

-U-H 


(CH3)3N 

OHO 


O= 

H 

A 


'— O-H 


H     O=P— O— H 


H  (C18H350) 

|  \ 

O     O  O     O     O 


(C16H810) 


H-C— C— C-H  H— C— C— C— H 


H    H    H 

Glycerophosphoric  acid 


H    H    H 

Lecithin 


Experiment  80. — Beat  a  raw  egg  to  a  foam,  allow  the  mass  to 
stand  until  most  of  the  insoluble  matter  has  subsided,  dilute  with 
about  five  times  the  bulk  of  water  and  filter  through  a  plaited 
filter.  This  solution  does  not  keep,  and  hence  must  be  made 
fresh  as  needed.  Portions  of  about  10  c.c.,  unless  otherwise 
directed,  should  be  used  for  the  following  experiments. 

Experiment  81. — Heat  a  portion  of  the  solution  to  boiling.  It 
will  not  coagulate,  add  a  few  drops  of  acetic  acid  and  boil  again, 
if  coagulation  does  not  occur,  add  more  acetic  acid  and  boil,  and 
proceed  in  this  way,  adding  small  quantities  of  the  acid  and  boiling 
for  a  few  seconds,  until  coagulation  is  obtained. 

Experiment  82. — Test  separate  portions  of  about  5  c.c.  of  the 
liquid  with  a  few  drops  each  of  sulphuric  acid,  hydrochloric  acid 
and  nitric  acid. 
14 


.   210  ORGANIC    CHEMISTRY. 

Experiment  83. — Add  5  c.c.  of  the  albumin  solution  to  20  c.c. 
of  water;  divide  the  solution  into  two  equal  portions  and  test  one 
with  a  few  drops  of  syrupy  phosphoric  acid  (orthophosphoric  acid) 
and  the  other  with  metaphosphoric  acid.  The  former  will  not 
coagulate,  the  latter  will  produce  immediate  coagulation.  If  o.i 
gram  metaphosphoric  acid  be  dissolved  in  water  and  the  solution 
kept  boiling  for  half  an  hour  the  coagulating  property  will  be  lost, 
as  the  acid  hydrolyses  to  orthophosphoric. 

Experiment  84. — Place  about  i  c.c.  of  strong  nitric  acid  in  a 
narrow  testtube  and  overlay  it  with  a  few  c.c.  of  solution  of  albu- 
min. It  is  best  to  use  a  somewhat  diluted  solution  for  this.  The 
overlaying  can  be  done  by  inclining  the  tube  very  much  and 
pouring  the  albumin  solution  down  the  side.  The  coagulated 
albumin  forms  a  ring  at  the  point  of  contact  between  the  two 
liquids.  This  is  known  as  Heller's  test. 

Experiment  85. — Portion  of  the  albumin  solution  may  also  be 
tested  by  the  following:  saturated  solution  of  picric  acid;  solution 
of  copper  sulphate;  solution  of  mercuric  chloride. 

Experiment  86. — Prepare  Millon's  reagent  by  adding  0.5  c.c. 
of  mercury  to  5  c.c.  of  strong  nitric  acid.  It  may  be  necessary  to 
complete  the  action  by  gentle  warming,  but  the  liquid  should  not 
be  boiled.  When  the  mercury  is  dissolved,  the  liquid  is  diluted 
with  twice  its  volume  of  water,  allowed  to  stand  for  some  hours 
and  decanted  from  any  deposit  that  may  have  formed.  It  does 
not  keep  long. 

Experiment  87. — Treat  a  solution  of  albumin  with  some  of  this 
reagent.  A  white  precipitate  is  formed  which  turns  brick-red  on 
boiling.  Other  proteids  give  similar  effects 

Experiment  88. — Treat  a  solid  proteid,  such  as  a  little  dried 
white  of  egg  or  a  piece  of  wool  or  silk  with  strong  nitric  acid.  A 
yellow  color  will  appear.  If  ammonium  hydroxide  be  added  to 
the  mass,  the  color  will  change  to  orange.  This  is  termed  the 
xanthoproteic  reaction. 

Experiment  89. — Prepare  a  stiff  jelly  from  gelatin  and  water, 
observing  that  it  can  be  liquefied  by  the  application  of  heat.  Add 
a  few  drops  of  formaldehyde  solution  to  a  small  portion  of  the 
jelly  and  allow  it  to  cool.  The  formaldehyde  combines  with  the 
gelatin  to  form  an  insoluble  compound  which  will  char  without 
melting. 


ENZYMS. 

Enzyms  are  nitrogenous  bodies  analogous  in  composition 
and  general  properties  to  ordinary  proteids,  but  are  distin- 
guished by  power  to  bring  about  transformations  without 
being  themselves  permanently  affected.  Nothing  is  known 
as  to  their  empirical  formulas;  in  fact,  they  have  not  been 
prepared  in  a  perfectly  pure  condition.  They  are  usually 
amorphous,  colorless  or  slightly  yellow,  soluble  in  water, 
but  not  appreciably  in  other  solvents.  The  solution  in 
water  soon  putrefies.  Some  enzyms  are  affected  in- 
juriously by  light,  and  all  of  them  lose  their  characteristic 
functions  when  heated,  resisting,  however,  this  treatment 
better  when  dry  than  in  solution.  Many  substances  re- 
strain the  action  of  enzyms;  some  of  these,  such  as  sali- 
cylic acid,  boric  acid  and  benzoic  acid  are  largely  used 
for  controlling  or  preventing  their  action.  Enzyms  are 
often  termed  "non-organised  ferments,"  ordinary  microbes 
being  designated  "organised  ferments." 

Each  enzym  has  its  peculiar  ''optimum"  condition, 
that  is,  that  under  which  it  is  most  active.  Conditions 
that  favor  one  enzym  often  restrain  or  interrupt  the 
action  of  others.  Thus,  pepsin  (pepsase),  the  principal 
enzym  of  gastric  juice,  is  favored  by  the  presence  of  a 
small  amount  of  hydrochloric  acid,  %  but  restrained  by  a 
larger  amount.  Trypsin  (trypsase),  the  corresponding 
enzym  of  the  pancreatic  secretion  is  favored  by  the 
presence  of  a  feebly  alkaline  body. 

The  manner  of  action  of  enzyms  is  not  known.  It  has 
been  suggested  that  they  combine  temporarily  with  the 
substances  involved  in  the  reaction  and  are  set  free  un- 
changed when  new  molecules  are  formed.  Thus,  the 
hydrolysis  of  sucrose  by  invertase  would  consist  in,  first, 


212  ORGANIC*  CHEMISTRY. 

a  combination  of  sucrose  molecules  and  water,  one  to  one, 
with  a  molecule  of  the  enzym;  then,  an  intermingling 
of  the  water  molecule  and  sucrose  molecule  to  the  ex- 
clusion of  the  enzym,  which  is  thus  liberated.  The 
molecule  formed  by  the  intermingling  of  the  water  and 
carbohydrate  is  immediately  broken  into  dextrose  and 
levulose.  The  enzym  is  free  to  repeat  its  action.  In 
theory,  therefore,  it  is  inexhaustible;  in  practice,  the 
accumulation  of  products  and  the  constantly  increasing 
dilution  interfere  with  and  ultimately  suspend  the  action. 
It  has  been  found  experimentally  that  invertase  can 
hydrolyse  100,000  times  its  weight  of  sucrose  and  still  be 
active. 

Enzyms  may  be  regarded  as  the  connecting  link  be- 
tween living  and  non-living  matter.  They  have  some  of 
the  characteristics  of  each  class,  but  they  have,  as  far  as 
known,  no  power  of  reproduction. 

The  following  are  some  important  enzyms,  with  their 
source  and  characteristic  actions : 

Diastase. — From  malt.  Converts  starch  into  maltose 
and  dextrin  by  hydrolysis.  Favored  by  mild  alkalinity 
of  solution  and  restrained  by  acidity  and  by  salicylic  acid. 

Takadiastase  (Japanese,  taka,  strong). — From  a  fungus 
that  grows  on  bran.  Similar  to  diastase  in  its  action. 

Amylopsin  (amylopsase). — From  pancreatic  secretion, 
similar  to  diastase. 

Invertase. — From  yeast,  hydrolyses  sucrose  to  a  mixture 
of  equal  parts  of  dextrose  and  levulose  (invert-sugar). 
Favored  by  very  slight  acidity. 

Synaptase. — From  tissues,  especially  seeds,  of  plants  of 
the  order  Rosaceae.  It  converts  amygdalin  by  hydrolysis 
into  benzaldehyde,  dextrose  and  hydrogen  cyanide. 

Myrosin  (myrosase). — Exists  in  white  and  black  mus- 


ENZYMS.  213 

tard.  It  hydrolyses  sinalbin  in  the  former  and  sinigrin 
in  the  latter,  producing  the  irritating  materials  upon  which 
the  local  action  of  mustard  depends. 

Pepsin  (pepsase). — The  principal  enzym  of  gastric 
juice.  It  hydrolyses  proteids  to  proteoses  and  finally  to 
peptones,  but  the  peptonising  action  is  slow  and  often 
incomplete.  Pepsin  is  most  active  in  the  presence  of  a 
small  amount  of  hydrochloric  acid. 

Trypsin  (trypsase). — One  of  the  enzyms  of  the  pan- 
creatic secretion.  It  hydrolyses  proteids  to  proteoses  and 
then  to  peptones,  being  more  rapid  than  pepsin.  It  acts 
best  in  feebly  alkaline  solution.  By  prolonged  action  pep- 
tones are  hydrolysed  to  leucin  and  tyrosin. 

Ptyalin  (ptyalase). — This  is  the  characteristic  enzym 
of  saliva.  It  hydrolyses  starch  to  maltose  and  dextrin, 
and  sucrose  to  dextrose  and  levulose. 

Steapsin  (steapsase). — An  enzym  of  the  pancreatic  se- 
cretion. It  hydrolyses  fats  to  glycerol  and  free  acids. 

A  similar  enzym  exists  in  the  castor  bean. 

The  juice  of  the  papaw  (Carica  papaya)  contains  en- 
zyms capable  of  digesting  proteids  and  starch.  The  juice 
of  the  pineapple  contains  an  enzym  that  digests  proteids. 

Catalase.  —  An  oxidising  enzym  obtained  from  fresh 
leaf-tobacco,  but  probably  widely  distributed.  It  de- 
composes hydrogen  dioxide. 

Rennin  (rennase)  is  found  in  gastric  juice,  especially 
in  that  of  the  fourth  stomach  of  the  calf.  It  is  some- 
times called  chymogen.  Its  characteristic  action  is  the 
coagulation  of  milk  which  is  due  to  a  hydrolytic  change 
in  the  caseinogen,  by  which  this  is  split  into  several  pro- 
teids some  of  which  precipitate  and  others  remain  in 
solution.  The  precipitate  and  liquid  are  termed,  re- 
spectively, " curds"  and  "whey."  Rennase  in  solution  is 


214  ORGANIC    CHEMISTRY. 

rendered  inactive  by  exposure  to  a  temperature  of  60°  to 
70°  which  is  somewhat  lower  than  that  required  for  most 
enzyms. 

Milk  contains  several  enzyms  that  have  digestive  and 
limited  oxidising  powers,  but  they  have  not  been  satis- 
factorily isolated. 

The  terms  proteolytic  (proteid-hydrolysing)  and  amy- 
lolytic  (starch-hydrolysing)  are  used  in  connection  with 
enzyms. 

Experiment  90. — Make  a  fresh  solution  of  a  small  amount  of 
i—2  diamidobenzene  (paraphenylene  diamine,  C6H4(NH2)2)  in  water, 
and  add  portions  of  it  to  boiled  and  unboiled  milk  in  separate 
testtubes.  Add  a  few  drops  of  hydrogen  dioxide  to  each  tube. 
A  deep  blue  color  is  produced  with  the  unboiled  milk  at  once,  but 
no  appreciable  color  with  the  boiled  milk  until  a  considerable 
time  has  elapsed.  The  color  is  due  probably  to  the  action  of  en- 
zyms in  the  milk  which  are  injured  by  the  heating. 

If  two  samples  of  milk  be  heated,  respectively,  to  75°  and  82°, 
it  will  be  found  that  the  portion  heated  to  the  lower  temperature 
will,  when  cold,  give  the  above  reaction,  while  that  heated  to  the 
higher  temperature  will  not  give  it.  At  some  point  between  these 
temperatures  is  the  "death  point"  of  the  enzym.  The  so-called 
"pasteurising"  temperature  lies  below  this  death  point.  It  is 
possible,  therefore,  to  distinguish  between  pasteurised  and  boiled 
(sterilised)  milk  by  this  test. 

Experiment  91. — Repeat  the  procedures  indicated  in  Experi- 
ment 31  with  the  variation  that,  before  adding  the  enzyms,  about 
o.i  gram  of  salicylic  acid  is  added  to  each  starch  solution.  It 
will  be  found  that  the  action  of  the  enzym  will  be  suspended,  very 
little  if  any  transformation  of  the  starch  taking  place.  It  is  pos- 
sible that  this  is  an  inhibitory  rather  than  an  enzymocide  action. 

Experiment  92. — Add  i  c.c.  of  strong,  pure  hydrochloric  acid 
to  150  c.c.  of  distilled  water,  and  dissolve,  without  heat,  in  this 
solution  0.009  gram  of  good  pepsin.  Mix  well  and  divide  the  liquid 
into  three  equal  parts.  It  contains  about  0.2  per  cent,  absolute 
hydrochloric  acid  and  0.003  per  cent,  pepsin,  being  approximately 
equivalent  to  normal  gastric  juice. 


ENZYMS.  215 

To  one  of  the  portions  of  solution  add  o.i  gram  of  boric  acid; 
to  another  portion  add  about  0.3  gram  of  sodium  sulphite.  To  all 
three  solutions  add  i  gram  each  of  finely-chopped  raw  meat,  and 
keep  them  at  a  temperature  of  from  38°  to  40°  for  six  hours.  It 
*will  be  found  that  the  sulphite  solution  has  a  marked  restraining 
action  on  the  pepsin  and  the  boric  acid  very  little,  if  any.  The 
actions  are  probably  inhibitory  rather  than  enzymocidal. 


INDEX. 


ABIETENE,  53 
Abietic  acid,  153 

—  anhydride,  153 
Abrastol,  141 
Absolute  alcohol,  63 
Acet  amide,  171 
Acetates,  76,  77 
Acetic  acid,  59,  60,  74,  76, 
80 

— • — ,    formation 

25 
•,    glacial,  76 


78, 
of, 


•  aldehyde,  71 

-  anhydride,  78 


Aceto-acetic  acid,  77 
Acetone,  73,  74 
Acetphenetidine,  191 
Acetylene,  96 
Acetyl  chloride,  80 
Acid  albuminate,  201,  204 
Acids,  60,  82 
Aconite,  187 
Aconitic  acid,  89 
Aconitine,  187 
Active  principles,  u 
Activity,  optical,  37 
Acrolein,  95 
Acrylic  acid,  92 
Additive,  115,  118 

—  compounds,  28 
Adenine,  197,  198 
Adipic  acid,  85 
Adjacent,  122 
Aerobic,  26,  193 
Agar-agar,  no 
Al,  47 

Albumen,  202 
Albuminates,  201,  204 
Albuminoids,  200,  202 
Albumins,  201,  202 


Albumins,  coagulated,  201 
Albumoses,  201,  205 
Alcohol,  6 1,  63 

— ,  absolute,  63 

,  amyl;  59,  60,  66 

-  butyl,  60,  61 

— ,  primary,  65 

,  secondary,  65 

-,  tertiary  ,"65 


,  caproic,  61 
,  cetyl,  6 1 
,  diatomic,  81 

ethyl,  59,  60,  61,  63 

grain,  63 

hexyl,  6 1 
-,  heptyl,  6 1 


—  methyl,  59,  60,  61 
— ,  monatomic,  61 
— ,  myricyl,  61 
— ,  nonyl,  61 
— ,  octyl,  6 1 
— ,  aenanthic,  61 
— ,  pentyl,  61,  66 
— ,  propyl,  60,  6 1 
— -,  triakontyl,  61 
Alcohols,  59,  60,  82 
— ,  primary,  65 
— -,  secondary,  65 
— ,  sulphur,  70 

,  tertiary,  65 

Aldehyde,  59,  71 

,  acetic,  71 

— ,  amyl,  60 

,  butyl,  60 

,  ethyl,  60,  71 

,  formation  of,  25 

— ,  group,  41 

,  methyl,  60,  62,  73 

— ,  propyl,  60 
Aldehydes,  60,  71 


217 


2l8 


INDEX. 


Aldose,  ioo 
Ale,  63 
Aliphatic,  46 

—  hydrocarbons,  49 
Alizarin,  135,  142,  144,  145 
Alkali  albuminate,  201,  204 
Alkaloids,  176 

,  animal,  190 

— ,  cadaveric,  190 
— ,  types  of,  189 
Alkyls,  51,  58 
Allo-isomerism,  39 
Alloxuric  bodies,  196 
Allyl,  94 
aldehyde,  91 

—  guaiacol,  132,  152 

—  isothiocyanate ,  165 

—  sulphide,  94 

—  thiocarb  amide  ,114 

—  thiocyanate,  114 
Allylene,  97 

Almond  shells,  183 
Alpha-derivatives,  141 

substitutions,  141 

Alphaamidonaphthalene ,  1 8 1 
Alphabet  anaphthol,  142 
Alphanaphthalenesulphonic 

acid,  141 

Alphanaphthol ,  141,  142,  183 
Amber,  153 
Amid,  41,  48 
Amides,  166,  171 
Amidoacetic  acid,  171,  173 
Amidobenzene ,  126 
Amidoethylsulphonic  acid,  173 
Amidobenzenesulphonic       acid, 

182 

Amidogen,  41 
Amidonaphthalene,  142 
Amidopurin,  198 
Amidosuccinamic  acid,  176 
Amin,  41,  48 
Amine,  n,  166 
Amines,  166 
Ammonia,  n 
Ammoniac,  154 
Ammonium  acetate,  76 

—  cyanate,  164 

—  derivatives,  166 

—  oxalate,  86 


Ammonium  valcrate,  79 
Amygdalin,  112,  161 
Amyl,  60 

acetate,  58,  69 

alcohol,  59,  60,  66 

aldehyde,  60 

chloride,  58 

ether,  60 

nitrite,  60,  69 

Amyloid,  202 
Amylolytic,  214 
Amylopsase,  212 
Amylopsin,  212 
Anaerobic,  26,  194 
Analysis,  proximate,  n 

— ,  ultimate,  n 
Anchoic  acid,  85 
Ane,  47 
Anethol,  152 
Aniline,  126,  183 

—  colors,  126 

—  oil,  126 

— ,  preparation  of,  138 

—  red,  146 

— ,  test  for,  138,  139 
Animal  oil,  Dippel's,  156 
Anise,  oil  of,  152 
Anthracene,  135,  142 
Anthranilic  acid,  137 
Antifebrin,  191 
Anthroquinone,  142 
Antigalline,  114 
Antipyretics,  191 
Antipyrin,  191 
Antitoxins,  194 
Antiseptics,  26 
Antizymotic,  25 
Apomorphine,  186 
Arabic,  gum,  no 
Arachidic  acid,  78 
Argol,  88 
Arsine,  167 
Arsonium,  167 
Asafetida,  154 

resin,  128 

Asaprol,  141 
Ase,  47 

Asparagin,  175 
Asymmetric  atoms,  37 

—  carbon,  37 


INDEX. 


219 


Atropine,  186 
Auramin,  145 
Axial  symmetric,  40 
Azo,  48 

-  -colors,  145 

-  -compounds,  176,  177 
Azoimide,  165 
Azoxy-group,  177 


BEER,  63 

Behenic  acid,  78 

Belladonna,  186 

Benzaldehyde,  124,  127 

Benzene,  116,  118 

— ,  production  of,  137 
— ,  structure  of,  119 

Benzenes,  115 

Benzidin,  143 

Benzin,  53 

Benzine,  53 

Benzoic  acid,  123,  127 

— ,  extraction  of ,  1 3  9 
— ,  test  for,  139 
—  sulphimide,  134 

Benzol,  118 

Benzolene,  53 

Benzoquinone,  133 

Benzoyl  glycocoll,  174 

Berberine,  187,  190 

Beta-derivatives,  141 

-  -substitutions,  141 

Betaine,  175 

,  y,  189,  196 

Betamidonaphthalene ,  1 8 1 

Betanaphthalenesulphonic  acid, 
141 

Betanaphthol,  141,  142,  183 

Betanaphtholazobenzene  ,178 

Benzyl  alcohol,  124,  125,  127 

Baking  powders,  88 

Balance,  Westphal,  14 

Balsam,  Peru,  154 

,  tolu,  154 

Bases,  xanthin,  196 

Birch,  oil  of,  68,  131,  152 

Birotation,  106 

Bismarck  brown,  145,  179 

Bitter  almond  oil,  124,  127 

Blood- albumin,  202 


Bloodroot,  187 
Brandy,  63 
British  gum,  no 
Bromine,  action  of,  28 
Bromo,  48 
Bromethane,  69 
Bromoform,  56 
Broom,  186 
Brucine,  187 
Brown,  Bismarck,  179 
Boiling  point,  17 
Borneol,  150 
Burgundy  pitch,  153 
Butane,  45,  50,  52,  54 

,  normal,  44 

Butine,  97 

Butter,  nature  of,  94 
Butyl,  60 

Butylacetic  acid,  175 
Butyl  alcohol,  60,  6 1 

,  primary,  65 

• — •  — • ,  secondary,  65 

, 'tertiary,  66 

aldehyde,  60 

—  ether,  60 

nitrate,  60 

Butyric  acid,  45,  60,  78,  94 

,  formation  of,  25 

Butyrin,  92 


CACAO, 189 
Cadaverine,  195 
Caffeine,  187,  189,  197 
Calabar  bean,  189 
Calcium  oxalate,  83,  86 
Calculus,  mulberry,  86 
Camphene,  148,  149 
Camphor,  116,  150 

— ,  artificial,  147 
,  Borneo,  150 

— ,  coal-tar,  140 

— ,  Japan,  150 

,  monobromated,  150 

Camphors,  149 
Cane-sugar,  105 
Caoutchouc,  149 
Capric  acid,  78 
Caproic  acid,  78,  94 
—  alcohol,  6 1 


220 


INDEX. 


Caprylic  acid,  78 
Carbamic  acid,  172 
Carbazol,  144 
Carbides,  97 
Carbinol,  62 
Carbohydrates,  73,  99 
Carbolic  acid,  126 
Carbon  chains,  42 

skeletons,  43 

tetrachloride,  55,  56 

Carboxy  benzene,  123,  127 
Carboxyl,  40 
Carron  oil,  80 
Carvacrol,  130 
Carvene,  149 
Casein,  201,  203 
Casein ogen,  203 
Castile  soap,  79 
Catalase,  213 
Citrene,  149 
Celluloid,  1 08 
Cellulose,  107 
Cerptic  acid,  78 
Cerium  oxalate',  86 
Cetyl  alcohol,  61 
Chains,  closed,  43 

,  open,  43 

Changes,  natural,  25 
Cheese,  204 
Cheese-poison,  180 
Chloral,  71,  72 

hydrate,  72 

Chlorine,  action  of,  28 
Chloro,  48 
Chlorbenzenes,  118 
Chloroform,  55 
Chlorophyll,  205 
Choline,  195,  208 
Chrysophanic  acid,  145 
Cinchona,  186 
Cinchonidine,  186 
Cinchonine,  186 
Cinnamic  aldehyde,  152 
Cinnamon  oil,  151,  152 
Citral,  150,  152 
Citric  acid,  89 
Citronellal,  150 
Cis-  form,  40 
Claret,  63 
Classification,  44 


I   Cloves,  oil  of,  152 

|   Coagulated  albumins,  201 

— ,  proteids,  201 
Coagulation,  201 
Coal-gas,  52 

-  -oil,  53 

— tar,  117 

camphor,  140 

• — colors,  126,  144 

kreasote,  126 

Coca,  187 
Cocaine,  187,  190 
Codeine,  186 
Coffee,  187 
Colchicine,  187 
Colchicum,  187 
Collagen,  202,  207 
Collidin,  158 
Collodion,  108 
Colophene,  149 
Colophony,  153 
Colors,  aniline,  144 

— ,  coal-tar,  144 
Combining  weight,  33 
Compound  ethers,  58,  60 

spirit  of  ether,  68 

Conine,  158,  186,  189 
Congo  red,  145,  179 
Consecutive,  122 
Constants,  12 
Constituents,  active,  n 
,  essential,  n 

— ,  proximate,  n 

— ,  ultimate,  n 
Copaiba,  153 
Copal,  153 
Copper  acetate,  77 

in  organic  bodies,  10 

Cosmoline,  53 
Cotton,  gun,  108 

— ,  negative,  108 

— ,  soluble,  1 08 
Coumarin,  155,  183 
Cream  of  tartar,  88 
Cresols,  127,  132 
Cresylic  acids,  132 
Crystallin,  201,  203 
Crystals,  Teichman's,  206 
Cryoscopy,  18 
Cumene,  124 


INDEX. 


221 


Curds,  213 
Cyanic  acids,  163 
Cyanides,  160 

— ,  complex,  161 
Cyanogen,  160 

—  hydroxide,  163 
Cyanuric  acid,  164 
Cyclic  hydrocarbons,  115 
Cyclo,  115 

Cyclopropane,  115,  116 
Cymene,  124 
Cymogene,  52 
Cystin,  175 
Cytoglobin,  202 


DAMMAR,  153 

Daturine,  188 

Decane,  54 

Decay,  25,  26 

Density,  vapor,  17 

Dehydrolysis,  27 

Dehydrolysing  agents,  27 

Derivatives,  24 

Desmotropic,  36 

Destructive  distillation,  24 

Dextrin,  109 

Dextrorotatory,  37 

Dextrose,  101,  184 

Di,  47 

Diamidobenzene,  214 

Diamidodiphenyl,  143 

Diamines,  167 

Diammoniums,  167 

Diatomic  alcohols,  Si 

Diastase,  212 

Diazo,  48 

-  -compounds,  176,  180 
— reaction,  Ehrlich's,  183 

Diazobenzene  butyrate,  180 

—  nitrate,  177 

—  sulphate,  177,  180 
Diazonium  compounds,  180 

—  sulphate,  177 
Diazotising,  178 
Dicarboxybenzenes,  133 
Dicarboxyl,  82,  83 
Dichloracetic  acid,  80 
Dichlormethane,  55 
Digallic  acid,  113 


Dihydroxy  ethane,  82 
Dinitroalphanaphthols  ,141 
Diose,  100 

Disaccharids,  99,  105 
Distillation,  destructive,  24 

,  fractional,  29 

Diethenediamine,  195 
Diethylamine,  168 
Di-isopropyl  methane,  54 
Dimethyl  ketone,  74 
Dimethylanilines,  126 
Dimethylbenzenes,  124 
Dimethylxanthin,  198 
Dimyricyl,  54 
Dipentene,  149 
Diphenyl,  144 

ketone,  142 

Dippe!' s  animal  oil,  156 
Diterpenes,  147 
Docosane,  54 
Dodecane,  54 
Dotriacontane,  54 
Drying  oils,  91,  96 
Dulcite,  105 
Dulcitol,  105 
Dutch  liquid,  Si 
Dynamite,  91 


EGG-ALBUMIN,  202 

white  of,  202 

• yolk,  203 

Eicosane,  54 
Elastin,  202,  207 
Electricity,  action  of,  30 
Eleoptenes,  149 
Emetine,  189 
Empirical  formula,  35 
Enanthylic  acid,  78 
Ene,  47 

Enzyms,  24,  46,  211 
Eosins,  136,  145 
Erythrosin,  136 
Eserine,  189 
Essential  oils,  147,  151 

principles,  n 

Esters,  58,  60,  68,  91 
Ethanal,  71 
Ethane,  43,  50,  52 
Ethene,  81 


INDEX. 


Ethene,  dichloride,  81 
-  glycol,  81,  82 

—  oxide,  82,  154 
lactic  acid,  84 

Ethenediamine,  169 
Ether,  67 

— ,  amyl,  60 

— ,  butyl,  60 

— ,  compound,  68 
— •- ,  compound  spirit  of,  68 

— ,  ethyl,  59,  60,  67 

— ,  methylethyl,  59,  68 

— ,  propyl,  60 

— ,  sulphuric,  67 
Ethers,  66,  82 

— ,  mixed,  59 
Ethereal  oil,  68 
Ethine,  96 
Ethyl,  60 

acetate,  69 

alcohol,  59,  60,  61,  63 

—  aldehyde,  59,  60,  71 
bromide,  69 

butyrate,  69,  79 

—  ether,  58-60 
nitrite,  60,  69,  70 

oxide,  67 

—  sulphide,  70 
.  Ethylene,  Si 

Eugenol,  130,  132,  152 
Exalgin,  192 
Extract,  Goulard's,  77 


FATS,  91 

Fatty-acids,  74,  93 
Fibrin,  201,  203 

ferment,  203 

Fibrinogen,  201,  203 

Firedamp,  52 

Fixed  oils,  91 

Fractional  distillation,  24,  29 

Freezing  point  of  solution,    18, 

32 

Fructose,  102 
Fruit  sugar,  102 
Fermentation,  25,  193 
Ferments  non-organised,  211 

,  organised,  211 

Ferricyanides,  162 


Ferrocyanides,  162 

Fluorescein,  135,  145 

Formaldehyde,  60,  62,  73 

Formalin,  73 

Formic  acid,  60,  75,  76,  78 

Formula,  30 

—   empirical,  35 

—  general,  36,  42 

—  graphic,  35 
—   molecular,  35 

—  rational,  35 

—  stereochemic,  36 

—  structural,  35 
Fuchsin,  145,  146 
Fulminates,  164 
Fulminic  acid,  163 
Fulminuric  acid,  164 
Fumaric  acid,  40 
Furfural,  155,  184 
Furfurane,  155 
Furfurosazone,  184 
Fusel  oil,  6 1,  64,  66 


GALACTOSE,  106 

Galbanum  resin,  128 

Gallic  acid,  114,  115 

Gallotannic  acid,  113 

Gamboge,  154 

Garlic,  oil  of,  95 

Gas,  olefiant,  81 

Gasolene,  52 

Gaultheria  oil,  152 

Gelatin,  207 

Gelsemine,  187 

General  formula,  36,  42 

Geraniol,  150,  152 

Glacial  acetic  acid,  76 

Gliadin,  208 

Globulins,  201,  203 

Glucose,  10 1,  184 

Glucosides,  112 

Glutenin,  208 

Glycerin,  90 

Glycerol,  80,  90 

formic  ester,  75 

Glycerophosphates,  93 

Glycerophosphoric  acid,  93,  209 
;   Glycerose,  101 
i  Glycin,  173 


INDEX. 


223 


Glycocoll,  173 

— ,  benzoyl,  174 
— ,  trimethyl,  175 

Glycogen,  108 

Glyceryl,  90 

Glycolic  acid,  82,  83 

Glyclos,  8 1 

Glycoproteids,  202 

Glycuronic  acid,  104 

Gold  orange,  178 

Golden  seal,  189 

Goulard's  extract,  77 

Grain  alcohol,  63 

Grape  sugar,  101 

Graphic  formula,  35 

Gravity,  specific,  12 

Green  soap,  80 

Guaiacol,  130,  153 
— ,  allyl,  132 

—  carbonate,  130 
Guaiac  resin,  153 
Guanine,  197 
Guarana,  189 

Gum  arabic,  no 

— ,  British,  no 

—  resins,  153,  154 
-  tragacanth,  110 

Gun-cotton,  107 
Gutta-percha,  149 


HEAT,  action  of,  24 
Heavy  oil  of  wine,  68 
Helianthin,  178 
Hemin,  206 
Hemiterpenes,  147 
Hemoglobins,  202,  205 
Henbane,  186 
Heneicosane,  54 
Hentriacontane,  54 
Heptacosane,  54 
Heptadecarie,  54 
Heptane,  50,  52,  54 
Heptyl  alcohol,  61 
Heroine,  188 
Hesperidine,  159 
Heterocyclic,  115 

compounds,  154 

Hexane,  50,  52,  54 
Hexadecane,  54 


Hexadecyl  alcohol,  61 
Hexane,  50,  52,  54 
Hexine,  97 

Hexmethenetetramine  ,170 
Hexose,  100,  101 

—  alcohols,  104 
Hexyl  alcohol,  69 
Hilum,  109 
Hippuric  acid,  174 
Hock,  63 

Hoffmann's  anodyne,  68 
Homatropine,  188 
Homocyclic,  115 
Homologous,  41 
Hyalogens,  202 
Hydrastine,  187 
Hydrastinine,  187 
Hydrazins,  177,  183 
Hydrazo,  177 
Hydrazoates,  166 
Hydrazobenzene,  177 
Hydrazo-group,  177 
Hydrazoic  acid,  165 
Hydrocarbon  radicles,  49 
Hydrocarbons,  aliphatic,  49 

,  cyclic,  115 

Hydrocyanic  acid,  161 
Hydrogen  cyanide,  161 
Hydrolysis,  26 
Hydrometers,  15 
Hydroxides,  60,  82 
Hydroxybenzene,  123,  126 
Hydroxyl,  40 
Hydroxymethane ,  62 
Hydroxymethylbenzene  ,125 
Hydroxynaphthalenes,  141 
Hydroxy  toluene,  125,  127,  132 
Hyenic  acid,  78 
Hypoxanthin,  197,  198 
Hyoscine,  186 
Hyoscyamine,  186 


IDE,  167 

Imid,  41,  48 

Imido-diphenyl,  144 

Imidogen,  41 

Imin,  41,  48 

Immiscible  solvent,  138,  185 

In,  47 


224 


INDEX. 


Indican,  114,  136 

Lactic  acid,  82 

Indigo,  136 

,      siercocnemic 

—  uiue,  i  -i  4 
Indigotin,  114,  136,  137 

iormuid,s  01,  37 
Lactic,  anhydride,  84 

Indin,  136 

Lactide,  84 

Indol,  136 

Lactose,  106,  184 

Indoxylcarboxylic  acid,  137 

Lager  beer,  63 

Ine,  46,  167 

Laurie  acid,  78 

Inulin,  109 

Lavender,  oil  of,  152 

Invertase,  105,  212 

Lead  acetate,  77 

Inversion,  105 

oxyacetate,  77 

Invert  sugar,  105 
Iodine,  action  of,  28 

JJJLcLoLtpl,    OO,    94 

—  ,  subacetate,  77 

,  numoer,  95 

,  sugar  01,  77 

lodo,  48 

•  water,  77 

lodoform,  56 

Lecithins,  196,  208 

Ipecac,  187 

Lemon,  salt  of,  86 

Isinglass,  208 

on,  i49>     5    >     5 

Iso,  39 

Leucic  acid,  83 

Isobutane,  44 

Leucins,  175 

Isocyanates,  165 

Leucomaines,  176,  190,  193,  194 

Isocyanic  acid,  163 

Levorotatory,  37 

Isocyanides,  160 

Levulose,  102,  109,  184 

Isocyclic,  115 

Light,  action  of,  30 

Isomeric,  39 

Ligroin,  52 

Isomerism,  43 

Limonene,  149,  152 

Isonitrile,  139 

Linalool,  150,  152 

I  so  vanillin,  124 

Liquid  smoke,  76 

Lutidine,  158 

Lyddite,  131 

JABORANDI,  187 

Lysol,  132 

KERATIN,  202,  207 

MADEIRA  wine,  63 

Keroselain,  53 

Magenta,  145,  146,  147 

Kerosene,  53 

Malachite  green,  145 

Ketones,  73,  74 

Maleic  acid,  40 

Ketonic  colors,  145 

Malic  acid,  87 

-  group,  41 

Malonic  acid,  82,  85 

Ketose,  100 

Malt,  212 

Kjeldahl  method,  n 

Maltose,  io6~,  184 

Kola,  187 

Malt  sugar,  106 

Koumyss,  83 

Manna,  105 

Kreasote,  130 

Margarin,  92 

coal  tar    1^6 

Margaric  acid,  78 

—  ,  test  for,  139 

Marsh  gas,  45,  51 

Martius'  yellow,  141 

Mandarin  orange,  178 

LAC,  153 

Mannitol,  104 

Lactalbumin,  201,  202 

Mannite,  104 

INDEX. 


225 


Mead,  63 
Mellissic  acid,  78 
Mellitic  acid,  123 
Melting  point,  15 
Menthol,  150 
Mercaptans,  70 
Mercury  fulminate,  164 
Mesotartaric  acid,  38 
Mesotomy,  84 
Meta,  121 

Metadihydroxybenzene  ,127 
Metamerism,  38,  39 
Methane,  43,  45,  50,  51 
Methemoglobin ,  206 
Methene,  81 

—  chloride,  55 

glycol,  82 

Methenyl,  91 

—  chloride,  55 

series,  90 

Methine,  96 

Methyl,  60 

acetanilid,  192 

—  acetate,  60,  68 

—  alcohol,  59,  60,  61 
aldehyde,  60,  62 

—  amidoacetate,  174 
amine,  169 

—  anilines,  126,  146 

chloride,  55,  58 

glycocoll,  174 

—  orange,  145,  178 

—  phenols,  132 

—  propane,  44 

—  pyndins,  158 
-  violet,  146 

salicylate,  68,  132,  152 

Methylated  spirit,  62 
Methylbenzene,  124 
Methylene  series,  90 

—  blue,  146 

ether,  58-60 

Methylethyl  ether,  68 
Millon's  reagent,  210 
Milk,  89 

albumin,  202 

— ,  pasteurised,  214 
— ,  sterilised,  214 
—  sugar,  83,  1 06 
Mindererus,  spirit  of,  76 


Mixed  ethers,  59 
Molecular  formula,  35 
Monatomic  alcohols,  61 

alcohol  radicle  series,  58 

Mono,  47 

Monobromated  camphor,  150 

Monochloracetic  acid,  80 

Monochlormethane,  55 

Monosaccharids,  99,  100 

Monose,  100 

Morphine,  186,  188,  190 

Morphium,  186 

Mucic  acid,  104 

Mucins,  202,  206 

Mulberry  calculus,  86 

Murexid  test,  193 

Muscarine,  196 

Mustard,   oil  of,    95,    114,    151, 

152,  165 

Myosin,  201,  203 
Myrbane,  oil  of,  126 
Myricyl  alcohol,  61 
Myristic  acid,  78 
Myronate,  potassium,  114 
Myrosase,  212 
Myrosin,  114,  212 
Myrrh,  154 


NAPHTHALENE, 140 

ring,  140 

Naphthol  green,  145 

yellow,  141,  145 

—  yellow  S,  141,  145 
Naphthols,  141,  142 
Narcotine,  186 
Natural  bases,  185 

changes,  25 

gas,  52 

Negative  cotton,  108 

Neurine,  195,  196 

Nicotine,  186 

Nitre,  sweet  spirit  of,  69 

Nitric  acid,  action  of,  27 

Nitro,  48 

Nitrobenzene,  123,  126,  127 

,  preparation  of,  138 

Nitro-colors,  145 

— compounds,  28 


226 


INDEX. 


Nitrogenated  oils,  151 
Nitroglycerin,  91 
Nitrophenols,  130,  139 
Nitroprussic  acid,  162 
Nitroso,  48 

colors,  145 

Nomenclature,  44 
Nonadecane,  54 
Nonane,  54 
Non-drying  oils,  92 

organised  ferments,  211 

Nonyl  alcohol,  61 
Nucleates,  207 
Nucleoalbumin,  201,  203 
Nucleohiston ,  202 
Nucleoproteids,  202 
Nucleus,  purin,  196 
Nux  vomica,  187 


OCTADECANE   54 

Octane,  54 
Octyl  alcohol,  61 
CEnanthic  alcohol,  61 
Oil,  aniline,  126 

,  anise,  152 

,  birch,  68,  131 

,  bitter-almond,  124,  127 


,  car r on,  80 

,  cinnamon,  151,  152 

,  cloves,  152 

,  fusel,  61,  64,  66 

,  garlic,  95 

— ,  lavender,  152 

,  lemon,  149,  151,  152 

— ,  mustard,  95,  114,  151 

,  myrbane,  126 

— ,  orange  peel,  149,  152 
— ,  orris,  152 

,  pennyroyal,  152 

,  peppermint,  152 

— ,  pimenta,  152 

1  rose,  152 

— ,  sassafras,  152 

,  thyme,  130 

,  turpentine,  147,  151 

,  violets,  152 

,  wine,  heavy,  68 

,  wintergreen  68,  151 

Oils,  drying,  91 


Oils,  essential,  151 

ethereal,  68 

fixed,  91 

—  nitrogenated,  151 

—  non-drying,  92 

oxygenated,  151 

sulphurated,  151 

volatile,  151 


Ol,  40,  47 
Olefiant  gas,  81 
Olefins,  51,  8 1 
Oleic  acid,  92,  95 
Olein,  92,  95 
Oleoresins,  153 
One,  47 
Onium,  167 
Open  chain,  46 

hydrocarbons,  49 

Opium,  1 86 
Optical  activity,  37 
Orange  III,  178 

flower  water,  151 

,  gold,  178 

,  mandarin,  178 

,  methyl,  178 

—  oil,  149 

—  peel  oil,  149,  152 
Orris  oil,  152 

Ortho,  121 

Osazones,  100,  103,  184 

Ose,  47 

Ovalbumin,  201,  202 

Oxalic  acid,  82,  83,  85 

Oxides,  60,  82 

Oxy,  1 20 

Oxybenzoic  acid,  124,  131 

Oxybutyric  acid,  82,  83 

Oxygen,  action  of,  25 

Oxygenated  oils,  151 

Oxyhemoglobin ,  206 

Oxypurin,  198 

Oxy  valeric  acid,  83 


PALMITIC  acid,  78 
Palmitin,  92 
Para,  39,  121 
Paraffin,  53 

• —  series,  51 

Paraform  aldehyde,  73 


INDEX. 


227 


Paralactic  acid,  84 
Paraldehyde,  71 
Paraxanthin,  197,  198 
Paper,  107 

— ,  parchment,  107 
Parchment  paper,  107 
Pasteurised  milk,  214 
Pawpaw*,  213 
Pelargonic  acid,  78 
Pellet  ierine,  187 
Pennyroyal,  oil  of,  152 
Pentadecane,  54 
Pentane,  50,  52,  54 
Pentatriacontane,  54 
Pen  tine,  97 
Pentose,  73,  100,  101 
Pentyl  alcohol,  61,  66 
Pentylic  acid,  79 
Peppermint,  oil  of,  152 
Pepsase,  211,  213 
Pepsin,  211,  213 
Peptones,  201,  205 
Percentage  composition,  30 
Peru  balsam,  154 
Petrolatum,  53 
Phellandrene,  149 
Phenacetin,  191,  192 
Phenates,  127 
Phenazone,  191 
Phenazine,  134 
Phene,  118 
Phenic  acid,  126 
Phenol,  123,  126,  183 
Phenolamidopropionic  acid,  175 
Phenol  disulphonic  acid,  139 
Phenolphthalein ,  315,  145 
Phenolsulphonic  acid,  129 

— ,  preparation   of, 

J39 

Phenol,  test  for,  139 
Phenyl,  120 

—  acid  sulphate,  129 
Phenylamine,  126 
Phenylates,.  127 
Phenyl  carbinol,  127 

ether,  135 

Phenylcarbamine,  139 
Phenyl  dimethylpyrazolon  ,191 
Phenylene,  120 
Phenylhydrazin,  177,  183 


Phenylhydrazin    hydrochloride, 

183,  184 

Phenylic  acid,  126 
Phenylmethane  derivatives,  145 
Phenylsulphuric  acid,  129 
Phloridzin,  128 
Phloroglucol,  128,  181 
Phosphines,  167 
Phosphonium,  167 
Phthal  amide,  137 
Phthaleins,  135 
Phthalic  acids,  133,  134 
Phthalins,  135 
Physostigmine,  187 
Picoline,  158 

Picrates,  preparation  of,  139 
Picric  acid,  124,  130,  145 
,  preparation  of, 

I39 

Pilocarpine,  189 
Pimelic  acid,  85 
Pimenta,  oil  of,  152 
Pinene,  147,  148,  152 
Piperazin,  170,  195 
Piperidin,  158 
Piperin,  158 
Piperonal,  132 
Pitch,  Burgundy,  153 
Plane,  symmetric,  40 
Plaster,  lead,  80 
Poison,  cheese-,  180 
Polarimeters,  20 
Polarimetry,  19 
Polymerism,  38,  39 
Polynucleated  compounds,  116 
Polysaccharids,  99,  107 
Polyterpenes,  147 
Pomegranate,  189 
Porter,  63 
Port  wine,  63 
Potassium,  action  of,  28 
—  cyanate,  164 

cyanide,  160 

isothiocyanate,  165 

—  thiocyanate,  165 
Primary  alcohols,  65 

amines,  168 

Principles,  active,  n 

,  essential,  n 

,  proximate,  n 


228 


INDEX. 


Principles,  ultimate,  n 

Proof  spirit,  63 

Propane,  43,  50,  52,  115 

Propargyl  alcohol,  98 

Propenyl,  90,  94 

Propine  hydroxide,  98 

Propionic  acid,  60,  78 

Propyl,  60 

alcohol,  60,  6 1 

aldehyde,  60 

ether,  60 

Propylene,  90 

Proteids,  200 

— ,  coagulated,  201 
— ,  vegetable,  208 

Proteolytic,  214 

Proteoses,  205 

Protocatechuic  aldehyde,  134 

acid,  153,  154 

Prussian  blue,  162 

Prussiate  of  potash,  red,  162 
— ,  yellow,  12 

Prussic  acid,  161 

Proximate  analysis,  n 
—  composition,  10 

principles,  n 

Pseudonucleins,  207 

Ptyalase,  213 

Ptyalin,  213 

Ptomaines,  176,  190,  193,  194 

Pulegone,  152 

Purin,  196,  207 

nucleus,  196 

Purins,  176 

— ,  endogenous,  199 

,  exogenous,  199 

Putrefaction,  25,  26,  193 

Putrescine,  195 

Pyknometer,  12 

Pyridin,  156 

hydride,  158 

Pyridins,  methyl,  158 

Pyro,  48 

Pyrogallic  acid,  128 

Pyrogallol,  128 

Pyroligneous  acid,  76 

Pyrotartaric  acid,  25,  85 

Pyroxylin,  107 

Pyrrin,  156 

Pyrrol,  155 


}UINIDINE  186 
Juinine,  186,  189 
Jjuinolin,  156 
Juinone,  133 
juinones,  133 


RACEMIC  acid,  38,  88   • 
Racemism,  38 
Radicles,  49,  60,  82 

,  organic,  40 

Raffinose,  106 
Rancidity,  92 
Rational  formula,  35 
Red  oil,  95 

,  Congo,  179 

Rennase,  213 
Rennin,  213 
Resin,  guaiac,  153 

soaps,  153 

Resins,  152 

— ,  gum,  154 

,  oleo,  154 

, true,  153 

Resorcin,  124,  127,  154 
Resorcinol,  124,  127,  154 

— ,  phthalein,  135 
Rhigolene,  52 
Rhodamin,  136,  145 
Rhus  glabra,  87 
Ring  symbols,  120 
Rocellic  acid,  85 
Rochelle  salt,  89 
Root  beer,  63 
Rosaniline,  146 
Rose  oil,  152 

water,  151 

Rosin,  153 
Rotatory  power,  22 


SABADILLA,  187 
Saccharic  acid,  104 
Saccharin,  134 

,  test  for,  139 

Salicylic  acid,  124,  131 

,  test  for,  138 

Salicin  ,112 
Saligenin,  112 
Salt  of  lemon,  86 


INDEX. 


229 


Salt  of  sorrel,  86 
Salt,  Rochelle,  89 
Sanguinarine,  187 
Sapo  mollis,  80,  93 
Saponification ,  91,  93 
Sarkolactic  acid,  84 
Sarkosin,  174 
Sassafras  oil,  152 
Sebacic  acid,  85 
Secondary  alcohols,  65 

amines,  168 

Seralbumin,  201;  202 

Sesquiterpenes,  147 

Shellac,  153 

Side-chain  substitution,  125 

Sinalblin,  114 

Sinigrin,  114 

Skatol,  136 

Smoke,  liquid,  76 

Smokeless  powder,  108 

Soap,  79,  91,  92,  93 

—  green,  80 

resin,  153 

Sodium,  action  of,  28 

—  ethoxide,  64 
• — •  ethylate,  64 

—  phenate,  131 
Soluble  cotton,  108 

tartar,  89 

Solidifying  point,  15 
Solution,  freezing  of,  18 
Sorbite,  105 
Sorbitol,  105 

Sorrel,  salt  of,  86 
Soudan  I,  178 
Sparteine,  186 
Specific  gravity,  12 

,  bottle,  12 

— ,  rotatory  power,  22 
Spirit  of  ether,  68 

,  methylated,  62 

of  mindererus,  76 

of  nitre,  sweet,  69 

of  wine,  63 

proof,  63 

,  wood,  6 1 


Spirits,  63 
Sprengel  tube,  12 
Spruce-beer,  63 
St.  Ignatia  bean,  189 


Starch, 108,  184 

solution ,  1 1  o 

Steapsase,  213 
Steapsin,  213 
Stearic  acid,  78,  79 
Stearin,  79,  92 
Stearoptenes,  149 
Stereochemic  formula,  36 
Sterilised  milk,  214 
Stibine,  167 
Stibonium,  167 
Structural  formula,  35 
Strychnine,  187 
Storax,  154 
Suberic  acid,  85 
Substitutive,  118 

compounds,  28 

Succinic  acid,  82,  85,  86 
Sucrose,  105,  184 
Sugar,  cane,  105 

milk,  83,  1 06. 

of  lead,  77 

Sulphanilic  acid,  124,  181 
Sulphethylic  acid,  58 
Sulpho,  48 
Sulphocyanates,  164 
Sulphonate,  48 
Sulphonation,  178 
Sulphonic,  48 
Sulphovinic  acid,  58 
Sulphur  alcohols,  70 
Sulphurated  oils,  151 
Sulphuric  ether,  67 
Sulphuric  acid,  action  of,  28 
Sylvestrine,  149 
Symmetric,  122 
Synaptase,  112,  161,  212 
Synthesis,  24 
Synthetic  compounds,  24 


TAKADIASTASE,  212 

Tannins,  113 

Tar,  beechwood,  130 

,  coal,  117 

Tartar,  88 

,  cream  of,  88 

emetic,  89 

,  soluble,  89 

Tartaric  acid,  38,1:87 


230 


INDEX. 


Taurin,  173 
Taurocholic  acid,  173 
Tautomeric,  36,  128,  133 
Tea,  187 

Teichmann's  crystals,  206 
Terebene,  149 
Terpenes,  116,  147,  151 
Terpinene,  148,  149 
Terpin  hydrate,  147 
Terpinolene,  149 
Tertiary  alcohols,  65 

amines,  168 

Tetrabromfluorescein ,  136 
Tetracosane,»54 
Tetrachlormethane,  55 
Tetradecane,  54 
Tetraiodofluorescein ,  136 
Tetramethenediamine  ,195 
Tetr  amethylatnrnoniuni ,  169 
Tetramethylbenzenes ,  124 
Tetramethyl  methane ,  5  4 
Tetramines,  167 
Tetrammoniums,  167 
Tetrazo-compounds,  179 
Tetrylic  acid,  78 
Tewfikose,  106 
Thalleioquin  reaction,  192 
Theine,  189 

Theobromine,  187,  189,  197 
Theophyllin,  187 
Thiacetic  acid,  71 
Thio,  48,  70 
Thiocyanates,  163,  164 
Thiophene,  155,  156 
Thiosinamin,  114 
Thrombin,  203 
Thyme  oil,  130 
Thymol,  124,  129 
Tobacco,  1 86 
Tolu  balsam,  154 
Toluene,  124 
Toluidines,  126,  146 
Toxins,  194 
Tragacanth,  no 
Trans-  form,  40 
Transformations,  24 
Tri,  47 

Triakontyl  alcohol,  61 
Triamines,  167 
Triammoniums,  167 


Tribromphenol,  139 
Trichloracetic  acid,  80 
Trichloraldehyde,  72 
Trichlorethene  glycol,  73 
Trichlormethane,  55 
Tricosane,  54 
Tridecane,  54 
Triethylamine,  168 
Trihydroxybenzene,  128 
Triketohexamethene ,  128 
Trimethene,  115 
Trimethylamine ,  169 
Trimethylbenzene,  124 
Trimethylethyl  methane,  54 
Trimethyl  methane,  54 
Trinitrophenol ,  124,  130 
Triose,  100,  101 
Trioxypurin,  198 
Trisaccharids,  99,  106 
Tritenyl,  90 

Tropeolin,  Porrier's,  178 
Trypsase,  211,  213 
Trypsin,  211,  213 
Turpentine,  153 

—  oil,  147,  151 
Ty  rosin,  175 
Tyrotoxicon,  180 

ULTIMATE  analysis,  n 

—  composition,  n 
—  constituents,  10 

Undecane,  54 
Unsaturated,  95 

—  fatty  bodies,  95 
Unsymmetric,  122 
Urea,  164,  171 

,  synthesis  of,  172 

Uric  acid,  197,  198 
,  test  for,  193 


VANILLIN,  124,  130,  181,  183 

,  synthetic,  132 

Valerianic  acid,  60,  78,  79 

Valeric  acid,  60,  78,  79 

Vaseline,  53 

Vinegar,  176 

Vapor  density,  17,31 

Vegetable  proteids,  208 

Veratrine,  187 


INDEX. 


23T 


Verdigris,  77 
Vinic  acids,  58 
Violets,  oil  of,  152 
Vitellin,  201,  203 
Volatile  oils,  151 


WATER  hemlock,  188 

,  lead,  77 

Wax  oil,  53 

Weight,  combining,  33 

Westphal  balance,  14 

Whey,  213 

Whiskey,  63 

Wine,  heavy  oil  of,  68 


Wine,  Madeira,  63 

,  Port,  63 

— ,  spirit  of,  63 
Wintergreen  oil,  68,  131 
Wood  spirit,  61 


XANTHIN,  197,  198 

bases,  196,  207 

Xylene,  124 
Xylidines,  126 


YELLOW  jasmine,  189 
,  naphthol,  41 


I  *>• 


